The hearth was in pre- and early-medieval times the holy of holies, the heart of the family. Where you would lay back and groove. Groove on the sound of the endless rains on the thatched roof, or on the sound of the sea water at your feet below. Sloshing against the grassy slopes of your house platform. A place that was warm and soulful. Filled with good spirits and minds. But how did those early Frisians manage to keep evil spirits, creatures and sickness at bay? How did they protect their yards and houses from this darkness? Well, dig this. They did it with grooves.
In this post we focus on the terp region (a terp being an artificial settlement platform). The terp culture existed in the west of Flanders, in the north of the Netherlands, in the northeast of Germany, and in the southwest of Denmark. This saltmarsh culture is as old as 2,600 years, when the first mounds were raised. After the Romans arrived at the beginning of the common era, we learn the names of these coastal dwellers. It was the territory of the Frisii or Fresones ‘Frisians’ in the west, and the Chauci more to the east living along the Wadden Sea coast.
Where exactly the border between the two tribes ran, cannot be determined anymore. According to the second-century Greek scholar Ptolemaeus, the river Ems was the border between the Phrissioi ‘Frisians’ and the Kauchoi ‘Chauci’. However, archaeological research shows closer kinship of the province Groningen with the Chauci in the east, than with the Frisians in the west (Nieuwhof 2021). Today, the river Ems is a border still. Now between Germany and the Netherlands, although the exact course of the border in the Dollart Bay is disputed between the two countries to this day.
After the Roman Period and the Migration Age, the whole area between Sincfala, i.e. inlet the Zwin in Flanders, and the river Weser had turned into territory of the Frisians. Also, much of the Wadden Sea coast of Schleswig-Holstein was colonized by Frisians from the Early Middle Ages onward. This is the region known today as Nordfriesland. Albeit cultural Frisian, region Nordfriesland was never part of political Frisia. From the High Middle Ages onward, western Frisia had become under control of counts of Flanders and of Holland. Remaining Frisia still encompassed the area between the river Vlie and the river Weser, in other words, current provinces Friesland and Groningen in the Netherlands, and regions Ostfriesland and Land Wursten in Germany. This more or less would continue to be the status quo until the sixteenth century, when the remainder of Frisia was dissolved too.
1. Oracle rods, spinning wool, and all that
The second-century Roman historian Tacitus wrote about the religious, pagan practices of the Germanic tribes in general. For example, that the people did not depict their idols as humans, and that they worshiped their gods in open-air somewhere at a lo, an open spot in a forest (Van Renswoude 2021). Women could be fortune-tellers and could possess the gift of prophecy. Casting lots and human sacrifice was also part of Germanic rituals. White horses, living ‘freely’ in the woods, could warn people, and could predict future events. There is very limited information about the gods the Frisians worshiped, both the Frisii and the Frisiavones. Several names of idols and matres we do know, but basically here our knowledge ends.
Almost 200 so-called oracle rods, being used to cast lots with, have been recovered, especially in the region northwest Germany and in the north of the Netherlands. These are dated from the Roman Period into the Middle Ages. The practice of casting lots was even incorporated into the late-eighth-century Lex Frisionum. The codex Lex Frisionum is the codification of the laws of the Frisians, and was ordered by the christian, Frankish kingdom to which Frisia was subjected to then. Therefore, the heathen practice of casting lots was modified as being a sign of God to determine who was guilty when in a riot someone was killed (Hines 2021). And, are we not talking about ‘it is someone’s destiny’ and do we not all love the lottery still? Casting lots, therefore, a pagan practice that survived Christianization. Oracle rods that have been preserved are made of silver, bronze, bone or horn. According to the same Tacitus, oracle rods were made of branches of fruit-bearing trees. It might these wooden lots did not survive the passage of time, of course.
Not only mankind was submitted to lot or destiny. Interestingly, the gods too. This make you wonder, what was lot then? Maybe it was the Fates of Greek mythology. The Fates, a trio of goddesses, determined the destiny of each and every human. One of the three goddesses was Clotho. It made wool and spun the so-called Thread of Life. Goddess Lachesis measured the length of the thread. Goddess Atropos cut the thread with its shears, meaning death. And, were it in old Germanic mythology not the three wool spinning maidens who lived next to the well Urđr, below the tree Uggdrasil? The maidens were named Urđr, Verđandi and Skuld, successively ‘what once was’, ‘what is born to be’, and ‘what will be’. Parallels with the Greel Fates are there, of course. Wool production, by the way, was a major and crucial economic activity for the Frisians, and its handicraft was protected by the Lex Frisionum mentioned above. If, for example, you would hurt a spinster, you had to face very severe punishment (check our post Haute couture from the salt marsh).
In European folklore, spinning and weaving wool was linked to the world of fairies and myths. Scottish weavers offered milk to the Highland fairy named Loireag. Then there is the Germanic winter spirit called Berchta, also known as Perchta, Frau Holle, or Mother Hulda. In this fairy tale the stepdaughter is pricked by a spinning wheel, which sets the events in motion. Also, Sleeping Beauty, or Toarnroaske or Doornroosje, is pricked by a spinning wheel. In Wales exists the fairy spinner Gwarwyn-a-Throt, and in Ireland the fairy spinner Girle Guairle. Furthermore, in medieval Scandinavia a female spirit called Seidr existed, meaning ‘thread’.
What were the gods of the early Frisians?
Firstly, the goddess Baduhenna. Known from the Battle of Baduhenna in AD 24. A battle just north of the modern city of Amsterdam between the Frisii ‘Frisians’ and the Roman Army, with on Roman side a body-count of 1,300 soldiers, again according Roman historian Tacitus. Maybe he exaggerated a bit.
Secondly, the goddess Hludana. Known from an inscription found at Xanten at the lower river Rhine in Germany. But also from an inscription found at Beetgum in province Friesland. Perhaps Hludana was worshiped by the Frisii living in the northwest of the Netherlands.
“To the goddess Hludana, the fishing contractors, when Quintus Valerius Secundus acted as tenant, fulfilled their vow willingly and deservedly”
Beetgum, the Netherlands
ca. first century AD
Thirdly, the matres Frisiavae. Known from an altar stone found in the town of Wissen, halfway between Cologne and Frankfurt. How it ended all the way up there, we have not got the foggiest idea. Certainly no Frisian territory anymore.
Fourthly, the goddess Nehalennia. Known from the hundreds of stone-altar parts found in the waters near the settlements of Domburg and Colijnsplaat, both in province Zeeland in the southwest of the Netherlands. This used to be the territory of the Frisiavones, the so-called Romanized Frisians (IJssennagger 2017). The part -avo means ‘belonging to/descending from’, so the people belonging to/descending from the Frisians (Neumann 2008). Not only Frisians, but ‘foreign’ skippers and traders traveling to Britannia from Trier, Cologne, Nijmegen etc., made offerings too to Nehalennia for a safe passage sailing the English Channel from Domburg and Colijnsplaat to Britannia. Read also our post Island the Walcheren: once Sodom and Gomorrah of the North Sea to find more about Nehalennia.
Lastly, fifthly, we mention the gods worshiped by Frisians known from votive inscriptions found all the way in northern Britain. These gods were not worshiped by your average Frisian. They were mercenaries in the Roman Army fighting in Britannia, and who were deployed at Hadrian’s Wall. The goddesses they worshiped were the two Alaisiagae, named Baudihillia and Friagabis. Read our post Frisian mercenaries in the Roman Army to read more in depth about these soldiers of fortune. Casually, these mercenaries also erected a pillar dedicated to the god of the thing. The thing being the Germanic assembly, also known as ting, ding or þing. The inscription of the Frisians is the oldest attestation of the name thing. Check our post The Thing is… to learn more about these soldiers with a democratic nature.
Of all the gods mentioned above, we do not suggest these were specific Frisian gods. We merely explained these were Germanic-Celtic gods (also) worshiped by Frisians. And not even that conclusion is definitive.
The picture of these ‘Frisian’ gods is that it were deities, goddesses, women. This fits nicely with what we know from other native Germanic-Celtic gods during the Roman Period, namely that they were all feminine too. It is also consistent with what Tacitus wrote about the specific powers attributed to women, mentioned above.
Mask of Boerdam
near Middelstum, the Netherlands
ca. 500 BC
On some of these rituals we know that they were still being practiced by the Frisian people in the Early Middle Ages. It was the seventh-century Saint Wulfram of Fontenelle, Archbishop of Sens, who pleaded with the heathen king Radbod of Frisia not to perform human sacrifices. A king described as the Enemy of Christ and as homo omni fera crudelior et omni lapide durior meaning: a human being more savage than any wild beast and harder than any stone. The killing could be executed either by hanging, or by tying someone up at a pole in the sea during ebb tide to let him or her drown slowly, after being castrated too. The latter practice is also documented in the already mentioned Lex Frisionum, where tying up someone to a pole to be drowned by the rising sea, was a punishment for sacrilege of temples, and therefore not a sacrifice per se but also a punishment.
By the way, Saint Wulfram is also known from the famous failed baptism of king Radbod. For this piece of history read our post Finally, king Redbad made his point in the European Commission – via Facebook.
And, as explained above, besides human sacrifice, the pagan practice of casting lots survived Christianization as well and was practiced in the Earl Middle Ages too.
The image presented above of the Boerdam mask, is easily associated with pagan rituals. However, when a school class asked the professor why it was not just made for fun, he not really had any arguments against it (Nijdam 2021).
2. How about those grooves?
Not any different from today, for terp dwellers too it was important that their land, farmyards and houses were free from evil spirits and souls, and from infectious diseases and sickness. The concept they used might have been a barrier model. Similar as the innovative models still being used by policymakers on security, defense and migration. Or like the force fields in ’80s science fiction movies or video games. The old Frisians too drew imaginary circles, with the hearth of the house annex farmstead being the center.
It fits very well with the physical, radial lay-out of a terp village. An artificial, circular mound on the flat and treeless tidal marshlands. The, first, outer ring were the salt marshes bordering the sea. The surrounding land started with soft mud, and toward the terp settlement it gradually became more solid and suitable for cattle to graze and even crops to grow. Often, the more inland marshlands were protected with low dikes, so-called summer dikes, which offered protection against regular, daily flooding. Spring tides and storm floods kept inundating the marshlands. Think of ten to twenty times yearly.
The next, second ring were the flanks or slopes of the terp itself, which were used for cultivating crowing crops, cutting grass sods for construction, and for crafts like weaving, blacksmithing, clay pottery production, and alike. The inner circle or third ring, was the terp village with houses and sweet water wells. Wells often contained deposits too, like spoke wheels, horse heads etc. Probably, also with a ritual meaning. An interesting artifact has been found in a dung pit in the terp of village Wartena in province Friesland, namely a wooden phallus. It is dated the Roman period.
When it comes to ward off evil spirits, souls, sicknesses and death, the hearth was the center. The hearth itself was protected as well, testifying frequent deposits found underneath it. Sometimes pieces of wooden wheels were excavated. If interested why wheels were buried and sacred, read our post Celtic-Frisian heritage: there’s no dealing with the Wheel of Fortune. Remember from that blogpost, do not mess with wheels when you are in Frisia!
From the already radiant patron of the salt-marsh landscape, now let’s turn to the circular barrier model of defense. We go through the four force fields from the inside out.
first line of defense
The first ring was the house, its walls and its doors. Underneath the poles supporting the roof and door frames, deposits were placed. These could be, for example, animal bones, terra sigillata and small pots with, perhaps, food offerings placed in it. Other deposits found during excavations of terps, are locks of hair. These locks might also have been part of rites of passage, for example a boy turning into a man or warrior, or a girl turning into a woman, and therefore not part of the energy giving rituals for the force field. Also, often at the base of the walls of the house, skulls of cows, horses and dogs were placed (see image below).
second line of defense
The second imaginary circle was created immediately around the house. Indeed, this was done by digging grooves, or furrows. Besides, these ditches probably functioned as little channels to collect water. Rainwater fell from the roof into these grooves and led into central sweetwater wells. The same grooves also functioned as protection against evil spirits. Collecting rainwater was vital for the terp dwellers, since sweetwater was often scarce on the salt marshes. The Roman Pliny the Elder wrote already in the first century about these water pits, read our post Shipwrecked people of the salt marshes.
third line of defense
Then, the third circle. This was the farmyard itself. The force field of the yard was energized with all kinds of deposits, mainly placed in pits. It could be clay pots, again with possible food offerings inside, animal bones and potsherds. Complete skeletons of horses and, regularly, of big dogs have been found too. For more about these fearsome war dogs, read our post How to bury your mother-in-law.
fourth line of defense
The final, fourth, circle was made by another round of grooves, furrows and ditches. These bordered the yard. Again, in these ditches deposits were placed. This could be in-tact (miniature) pots, pottery, potsherds and animal bones. Not always, but pots and pottery also were smashed when deposited. Sometimes even bronze Roman statuettes and brooches were placed in the grooves. If the ditches were filled, e.g. because of a terp enlargement, again ritual deposits were being made. Why disband a good protective force field, after it was sealed off? Or was it a way to say ‘thanks’ for all the protective work done the years before? Some archaeologists argue that deposits were being made when a groove or ditch was dug in new land as a means of compensation for the goddesses and spirits for the infringement of ‘their’ lands (Tuin 2015).
But not only bones and skulls of animals were used…
Archaeological excavations in the terp region identified human bones and skulls literally lying all over the place. These bones were used to strengthen the protective power of the circle. Albeit the dead normally were not buried in the terp mound itself, and excarnation above ground was the common funeral practice during the Roman Period (Nieuwhof 2015), occasionally complete inhumations, both adults and infants, were found under the floor of the house, or on the yard. Mostly within a radius of ten to twenty meters. Mandible, femur, tibia, vertebra and skull fragments, all have been found in pits, grooves and ditches.
Do not be too alarmed. Ritual use of human bone is very comparable with the relics of Catholic saints of today. These relics still serve as an intermediary between heaven and earth (Van Eijnatten & Van Lieburg 2006), and as a protection against evil and sickness. Bones of saints are still being carried around during processions, are immured in church walls, and are entombed in holy altars.
Human skull bone was even worked. Polished and a hole was perforated into it, so it could be used as an amulet. These human amulets and cups have been found in the terps of Arum-Baarderburen, Marrum-De Beer, Stiens-Kramer, Hempens-Glins, Ezinge, and of Wierhuizen. Your deceased mother or grandma always close around your neck. Maybe making it difficult for you to breathe freely still. The worked skull pieces might even have been used as cups. Or, another possibility, were it former enemies hanging around their necks? If you think all this is just too weird again, think of the millions of people who perform the holy rite of the Eucharist today, and who then consume the blood and flesh of Christ.
Also, read our post mentioned earlier How to bury your mother-in-law to learn more about the pagan excarnation practices at the salt marshes, including the role the big Frisian hell hounds had in releasing the soul from the flesh.
Archaeologist Nieuwhof gives also as possible explanation for the finds of worked human bone that it was part of rituals to establish the identity of land and house property through the ‘presence’ of ancestors. To tie the family to the land.
Many of the practices above date from the Roman Period, the Iron Age. But some of the rites and rituals probably survived well into the Early Middle Ages. By then, the Frisians had become your average, classic Germanic tribe. No longer the feminine gods, but the well-known testosterone gods Donar (Thor), Wodan (Odin), and the typical Frisian god Foseti. The latter probably worshiped at the Frisian red island Heligoland high at the North Sea. But Germanic goddesses existed too, of which Freyja was the most important in the region. One of the pre-medieval superstitious practices that had survived, is digging grooves or furrows.
Proof of the pagan practice of digging grooves in the Early Middle Ages, is archived in the devotional Vatican. It is the Codex Palatinus Latinus 577. A book that contains the Indiculus superstitionum et paganiarum ‘Small index of superstitious and pagan practices’, and also includes the fascinating Baptismal Vow of Utrecht. The Baptismal Vow was written in the year 742 or 743, opinions differ, and probably was used by Saint Boniface to Christianize the unruly Saxons and the Frisians in the eighth century.
A relatively obscure idol appears in the vow, namely the god Saxnot. Maybe worshiped by Frisians too, for the Frisians are by and large of Saxon origin (check out our post Have a Frisians Cocktail for more about their origin). The Baptismal Vow of Utrecht is also curious, since it is not written in Latin but in an odd mixture of Old Saxon, Old Frisian and Old Low Franconian. We can compare it with the fusion languages of Papiamento and Patois of today. Picture how the Anglo-Saxon bishop Boniface baptized pagan Saxons and Frisians reciting this creole vow with, of course, a solemn expression on his face:
Forsachistu diobolæ? Et respondeat: Ec forsacho diabolæ.
End allum diobolgeldæ? Respondeat: End ec forsacho allum diobolgeldæ.
End allum dioboles uuercum? Respondeat: End ec forsacho allum dioboles uuercum and uuordum, Thunær ende Uoden ende Saxnote ende allum them unholdum the hira genotas sint.
Gelobistu in Got alamehtigan fadær? Ec gelobo in Got alamehtigan fadær.
Gelobistu in Crist Godes suno? Ec gelobo in Crist Godes suno.
Gelobistu in halogen gast? Ec gelobo in halogan gast.
Do you forsake the Devil? And the answer must be: I renounce the Devil.
And all Devil’s money [sacrifices to the devil]? The answer must be: And I forsake Devil’s money.
And all Devil’s work? The answer must be: And I forsake all Devil’s works and words Donar and Wodan and Saxnot and all demons who are their followers.
Do you believe in God the Almighty Father? I believe in God the Almighty Father.
Do you believe in Christ, God’s Son? I believe in Christ, God’s Son.
Do you believe in the Holy Spirit? I believe in the Holy Spirit.
3. The indiculus ‘index’ itself
This index is without the book and that has been lost. So, this occasion we must judge the book by its cover. The index is written in Latin language, although it contains a few Germanic words that they probably could not translate back then. These are the words nimida (i.e. the sanctuary in the forest, and maybe the same spot Tacitus identified), nodfyr (translated as ‘holy fire’, and considered the oldest Low Franconian/Old Dutch word survived) and yrias (a kind of run).
In total thirty rituals and pagan practices are listed in the Indiculus.
- de sacrilegio ad sepulchra mortuorum, ‘of sacrilege at the graves of the dead’
- de sacrilegio super defunctos i.e. dadsisas, ‘of sacrilege to the dead, i.e. the death feast’
- de spurcalibus in Februario, ‘of swinish feasts in February’
- de casulis i.e. fanis, ‘of small buildings, i.e. shrines’
- de sacrilegiis per ecclesias, ‘of sacrilege in churches’
- de sacris silvarum, quae nimidas vocant, ‘of sanctuaries in woods they call nimidas’
- de his, quae faciunt super petras, ‘of those things they do upon the rocks’
- de sacris Mercurii vel Iovis, ‘of the sanctuaries of Mercury and Jupiter’
- de sacrificio, quod fit alicui sanctorum, ‘of the sacrificial service for some saints’
- de philacteriis et ligaturis, ‘of amulets and knots’
- de fontibus sacrificiorum, ‘of fountains of sacrifices’
- de incantationibus, ‘of incantations’
- de auguriis vel avium vel equorum vel bovum stercora vel sternutationes, ‘of auguries from manure from birds, horses or cattle and sneezing’
- de divinis vel sortilegis, ‘of diviners or sorcerers’
- de igne fricato de ligno i.e. nodfyr, ‘of the fire made from the friction of wood, i.e. nodfyr’
- de cerebro animalium, ‘of the brain of animals’
- de observatione pagana in foco vel in inchoatione rei alicuius, ‘of the observance of the pagans on the hearth, or at the start of any business’
- de incertis locis, que (quae) colunt pro sanctis, ‘of undetermined places they worship as sanctuary’
- de petendo, quod boni vocant sanctae Mariae, ‘of bed-straw which good people call Saint Mary’
- de feriis, quae faciunt Iovi vel Mercurio, ‘of feasts they hold for Jupiter or Mercury’
- de lunae defectione, quod dicunt vince luna, ‘of the lunar eclipse they call vince luna’
- de tempestatibus et cornibus et cocleis, ‘of creating storms and horns and snail shells’
- de sulcis circa villas, ‘of grooves encircling houses’
- de pagano cursu, quem yrias nominant, scis[s]is pannis vel calciamentis, ‘of the pagan race they call yrias, with torn clothes and shoes’
- de eo, quod sibi sanctos fingunt quoslibet mortuos, ‘of this, what they describe as a holy death’
- de simulacro de consparsa farina, ‘of the idol made of dough’
- de simulacris de pannis factis, ‘of idols made from torn clothes’
- de simulacro, quod per campos portant, ‘of the idol carried through fields’
- de ligneis pedibus vel manibus pagano ritu, ‘of wooden feet and hands in a pagan rite’
- de eo, quod credunt, quia femine(ae) lunam comende(n)t, quod possint corda hominum tollere iuxta paganos, ‘of this, which they believe, that women command the moon, so they can take out people’s heart according to the pagans’
Practice number 23 is the one about grooves or ditches, often translated as furrows. Since the Indiculus is very general, it is difficult or impossible to really understand what the superstitious rituals actually did look like, and what their purpose was. Nevertheless, it gives us a rare insight into some of the pre-Christian practices of the Saxons and the Frisians in the Early Middle Ages.
Although not in the terp region, the practice of grooves in ritual practices has been found in a clay mound at present-day town of Katwijk in province Zuid Holland as well. This terp was actually a burial ground, more or less during the Roman Period. Here, circular grooves encircling cremation graves have been excavated. The cemetery of the village of Oosterbeintum in province Friesland also has circular ditches. From other burial grounds from the Iron Age in the Netherlands we know that these grounds were considered transitional places between earth and the world of spirits. The burial grounds were often encircled by furrows. More in general, Late Bronze Age interments, often in an urn, where placed in a pit surrounded by a circular or oblong ring-ditch (Waterbolk 1977).
The (religious) practice or ritual of making grooves did not stop in the Middle Ages. Churches in Westphalia, Germany and in the Netherlands have grooves scratched into stones on the exterior of ca. 25 cm long and 5 to 6 cm wide and deep. This practice continued well into the twentieth century. You can find them for example at the southern door of the church of the village of Loppersum, on the sarcophagus in the church of the village of Termunten, in the Saint Boniface church in the village of Wehe-Den Hoorn, and on a tomb lid at the former cloister in the village of Ter Apel. All these examples are found in province Groningen. Also, the teeny tiny terp village of Jannum in province Friesland has lids of sarcophagus and altar stones with grooves. But in many more places in the Netherlands grooves can be found, like the churches in the towns of Aardenburg, Goes, Naarden, Kortgene and Rhoon.
Mostly these grooves are made in sandstone and the gravel that came of it was often dissolved in water and used to cure illnesses. By the way, not only gravel was used, but pulverized human bone as well. This latter practice was documented by historian Gregory of Tours in the sixth century.
Chinese Medicine – Only recently the Chinese government legalized rhino and tiger bone for medical purposes. If people still believe in the medicinal remedy of bone, would it not be better if they return to the old practices, and use human bone again or the gravel of holy stones again?
Stones as such, besides grooves carved into it, were in the landscape of Frisia a scarcity. Perhaps that contributed to the often spiritual or religious meaning of stones as well. Think of the stone Archbishop Rimbert of Bremen prayed upon to ask for God’s help for the Frisians to defeat the Vikings near the town of Norden in Ostfriesland. Read our post A Theelacht: what a great idea! to learn more about this miracle, because it succeeded. The stone can be found at the Liudger Church of Norden. But also think of the Devil’s stone at the village of Godlinze, the stone at the village of Holwierde, the stone at Westerklief at the former island of Wieringen, and the stones on the graveyard of the village of Rinsumageest. All rocks shrouded with stories. Lastly, stones frequently appear in sagas too. Like in the East-Frisian sagas of Der Blutstein in Stapelmoor, Der Marienstein in Stapelmoor, Der Hilgenstein, Die Steine von Osteel, and Der Vosskutt in Burhafe, and in the saga Der Drachenstein bei Donnern near Bremerhaven.
After reading all of the above, from human skull cups and amulets hanging around necks, to inhumations under house floors, bones placed in grooves, the Indicules, and mystical stones, we leave it now to the reader’s own imagination what the world and people looked like from the Roman period to the Early Middle Ages. Knowing, of course, (a) lot had changed between these two eras.
Baby, just sing about the groove (Sing it)
Note 1 – The Roman gods Jupiter and Mercury, as mentioned in the pagan practices number 8 and 20 of the indiculus, were replaced in the Germanic religion by respectively Donar/ Thor and Wodan/ Odin. After Christianization, these gods were replaced yet again, this time by respectively the apostle Saint Peter and Archangel Michael.
Note 2 – Frisians shaping their landscape by milling uncountable grooves and ditches and other waterways, even received their tribes name because of it 2,000 years ago. Read our post A severe case of inattentional blindness: the Frisian tribe’s name.
Note 3 – featured image Kierin Magenta Kirby aka Lady Miss Kier.
- Creedence Clearwater Revival, I Put a Spell on You (1968)
- Deee-Lite, Groove Is in the Heart (1990)
- Coulthard, S., A Short History of the World According to Sheep (2020)
- Eijnatten, van J. & Lieburg, van F., Nederlandse religiegeschiedenis (2006)
- Fernández-Götz, M. & Roymans, N., The Politics of Identity: Late Iron Age Sanctuaries in the Rhineland (2015)
- Fontijn, D., Economies of Destruction. How the systematic destruction of valuables created value in Bronze Age Europe c. 2300-500 BC (2020)
- Groenewoudt, B., Beek, van R. & Groothedde, M., Christianisation and the Afterlife of Pagan Open-Air Cult Sites. Evidence from the Northern Frankish Frontier (2016)
- Hines, J., Religion and conversion amongst the Frisians (2021)
- Hunink, V., Tacitus. In moerassen & donkere wouden. De Romeinen in Germanië (2015)
- In Pago Wirense, Legends and Folklore on Wieringen (website)
- Knol, E., et al, The medieval cemetery of Oosterbeintum (Friesland) (1996)
- Laan, van der J., De bijzondere houten voorwerpen uit de opgravingen in Ezinge (2016)
- Lendering, J., Hludana. Livius.org (2004)
- Mees, K., Burial, Landscape and Identity in Early Medieval Wessex (2019)
- Neumann, G., Namenstudien zum Altgermanischen (2008)
- Nicolay, J., Het kweldergebied als cultuurlandschap: een model (2015)
- Nieuwhof, A., Dagelijks leven op terpen en wierden (2018)
- Nieuwhof, A., Eight human skulls in a dung heap and more. Ritual practice in the terp region of the northern Netherlands 600 BC – AD 300 (2015)
- Nieuwhof, A., Graven en botten. Menselijke resten in Ezinge (2014)
- Nieuwhof, A., The Frisians and their Pottery: Social Relations before and after the Fourth Century AD (2021)
- Oneindig Noord-Holland, Een idool van hout (2012)
- Prummel, W. & Hullegie, A.G.J., Bewerkte voorhoofdsbeenderen van pasgeboren kalveren uit drie terpen (2016)
- Renswoude, van O., De weg naar een nieuwe ee (2021)
- Renswoude, van O., Hof, harg en hal: het heten van heiligdommen (2021)
- Renswoude, van O., Hoge ouderdom op de Veluwe (2021)
- Renswoude, van O., Woen bij de Friezen (2021)
- Sagas from the Sea: The Northern world, The Time for Fated Men: Destiny & Free Will in the Northern World (2021)
- Saupe, H.A., Der Indiculus Superstitionum Et Paganiarum. Ein Verzeichnis Heidnischer Und Aberglaubischer Gebrauche Und Meinungen Aus Der Zeit Karls Grossen (1891)
- Schuyf, J., Heidense heiligdommen. Zichtbare sporen van een verloren verleden (2019)
- Siefkes, W., Ostfriesische Sagen und sagenhafte Geschichten (1963)
- Tuin, B., Rondslingerend menselijk bot? (2015)
- Tuuk, van der L., De Friezen. De vroegste geschiedenis van het Nederlandse kustgebied (2013)
- Visser, A., Scheppers van aarde (2016)
- Waterbolk, H.T., Walled enclosures of the Iron Age in the North of the Netherlands (1977)