With regard to the rites of the old Scandinavian religion a considerable amount of information has been preserved, although mainly relating to one part of the subject, the offering of sacrifice. It is clear that this was the central feature in the worship of the gods, and the great means towards propitiating their favour or averting their displeasure. Hence the verb blóta, which was the distinctive word for worshipping the heathen gods, very frequently (if not usually) implies the accompaniment of sacrifice; and the noun blót similarly means either the act of worship or that of sacrifice. In the case of the verb, the object of worship stands in the accusative case, the thing sacrificed in the dative, the original sense being 'to worship (the gods) with something.' In this killing of living things as an offering to the divine powers lay one of the most obvious differences between the old religion and the new, and it is consequently one which holds a prominent place in the accounts of the struggle between heathenism and Christianity. One of the first objects aimed at by the kings who adopted the new faith was the suppression of the practice in every form, while the adherents of the old religion clung to it tenaciously as long as they could. Even after Christianity was the established religion of Norway, it was still thought necessary to remind the people that all blót were forbidden, whether to 'the heathen gods, mounds, or sacred cairns.' Here and in other passages where the word is similarly employed, it may be assumed that sacrifices are to be thought of as an essential part of the heathen worship.

Sacrifice might be offered either by individuals on their own account, or by some prominent man on behalf of the community. It was, indeed, the duty of the latter to 'keep up the sacrifices,' on which the public peace and prosperity were believed largely to depend. The king as head of his people was especially bound to maintain this religious rite, and the adoption of Christianity by the Norwegian kings naturally brought them into direct collision with the national feeling on this point. When King Hákon in 952 proposed that his subjects should worship Christ, give up the heathen gods and the sacrifices to them, and keep holy each seventh day, he was met by the reply that they desired him rather to follow the custom of his father, and 'sacrifice for peace and plenty to them.' On the other hand, the importance attached to the practice by the more religious among the people is shown in the case of Loft the Old, who emigrated to Iceland from Gaular in Norway. He 'went abroad every third summer on his own account and that of his uncle Flosi, to sacrifice at that temple in Gaular of which his mother's father, Thorbjörn, had been the custodian.'

The extent to which the common people shared in the expense attendant on such sacrifices seems to have varied according to circumstances. In some cases the offering was a collective one; in others some great man showed his wealth and munificence by providing it entirely from his own resources. Probably the latter course was somewhat exceptional, as Snorri says of Earl Sigurd, that 'he did a thing that was widely famed: he made a great sacrificial feast at Hladir, and stood all the expense of it himself.' This he confirms by citing a verse from a poem in praise of Sigurd, composed by the Icelandic poet Kormak. Otherwise, he states, 'it was the old custom, when there was to be a sacrifice, that all the householders should come to the place where the temple was, and bring there the provisions they would require while the festival lasted.' According to Adam of Bremen, too, the great festival which was celebrated every nine years at Upsala was maintained by contributions from the whole Swedish people, and attendance at it was compulsory; even those who had adopted Christianity were only exempted on payment of a fine. The national character of the festival is also certified by Snorri, who calls it the 'chief blót,' and says it was held to obtain peace and victory for the Swedish king.

The actual sacrifice consisted in the killing of various animals, usually oxen, horses, sheep, or swine, but on special occasions even human beings were offered to the gods. At the great Upsala festival, according to Adam's account, nine male animals of each kind were offered, as well as men; and a Christian eye-witness reported having seen seventy-two carcases of slaughtered men and beasts (dogs and horses) suspended together from the trees of the sacred grove adjoining the temple. Whether this custom of hanging up the bodies of the offerings was practised elsewhere in Scandinavia is unknown, but the connection between Odin and death by hanging makes it probable that it was more widely known than appears. In Denmark also human victims were offered along with animals; according to Thietmar's chronicle the great gathering in this country took place at Lejre (near Roskilde in Sjælland) every nine years, in the month of January. The sacrifice here consisted of ninety-nine men and as many horses, dogs, and cocks (the latter being offered in place of hawks). How the victims were selected or obtained is not stated; but it is probable that they were usually captives taken in war, criminals, or thralls. In Sweden, indeed, strangers appear to have run some risk of being selected as victims; in 997 the Icelandic poet Hallfred nearly met with this fate. In early times, however, the Swedes were credited with having burned one of their kings in his own house as an offering to Odin, in order to dispel a famine which they believed was due to his slackness in maintaining the sacrifices. One of the early kings was also reported to have offered up nine of his sons in succession to Odin, to obtain long life for himself. In an account of the heathen period in the isle of Gotland, which is given in Guta Saga, it is said that 'they sacrificed their sons and daughters and their cattle. All the land had its highest sacrifices with folk (=human beings), as also had each third (of the country) by itself; but the smaller districts had lesser sacrifices with cattle.'

In Norway and Iceland human sacrifices appear to have been more exceptional, and only resorted to in extreme cases. The usual nature of the victims is clearly indicated by the words assigned to King Olaf Tryggvason in 998, when he found his subjects obstinate in their determination to hold the midsummer blót. He then threatened 'to make it the greatest kind of sacrifice that is in use, and offer up men; and I will not choose thralls or criminals, but will select the most distinguished men to give to the gods.' At the very crisis of the conflict between paganism and Christianity in Iceland, in the year 1000, the adherents of the old religion resolved to sacrifice two men out of each quarter, and 'called upon the heathen gods not to let Christianity overrun the country.' Then Hjalti and Gizur held a meeting of the Christians, and said that they would also make an offering of as many men. 'The heathens,' they said, 'sacrifice the worst men, and cast them over rocks or cliffs; but we shall choose the best men, and call it a gift for victory to our Lord Jesus Christ.' Various methods appear to have been in use besides that mentioned here; at Thorsness, in the west of Iceland, tradition long pointed out the 'doom-ring,' in which men had been adjudged for sacrifice, and the stone within it — called Thor's stone — on which they were killed by being broken, 'and the stain of blood is still to be seen on it.' Another source speaks of human victims as having been sunk in a fen close to the temple on Kjalarness, which is supported by Adam of Bremen's statement that near the temple of Upsala was a fountain in which 'a living man' was immersed. A 'sacrificial pit' is also mentioned in Vatnsdæla Saga, where one Thorolf was believed to sacrifice both men and cattle. That in exceptional cases the victim may have been of higher standing than the thrall or criminal is possible enough; as late as 985 Earl Hákon in Norway is credited with having given his young son as an offering to Thorgerd, when he prayed to her for victory over the vikings of Jómsborg. In other cases, such as that of Hallstein, who 'gave his son to Thor' in order that the god might send him pillars for his house, the language is ambiguous, and may imply dedication rather than sacrifice. When the sacrifice consisted of animals which might be used for human food, it was apparently only the blood which was regarded as belonging to the gods. To this was given the name of hlaut, and it has already been stated (p. 41) that special bowls were kept to receive it in. It was then smeared or sprinkled by means of twigs, not only upon the altars and the walls of the temples (both outside and in), but also upon the assembled people. The flesh was then boiled in large pots over the fires which burned in the middle of the temple, and was eaten by the worshippers, after being consecrated by the chief man present. A prominent feature, at least of the more important festivals, was the use of horse-flesh for this purpose — a practice so intimately associated with heathenism that its abandonment was strictly prescribed to those who accepted Christianity. This appears in the strongest light in the case of Hákon the Good, who was finally forced to appease his heathen subjects by eating some pieces of horse-liver. In Iceland, however, it was permitted for a few years after the new faith was publicly adopted.

When the drinking began, the horns of ale were carried round the fire and solemnly dedicated to various gods. The first full or toast was assigned to Odin (see p. 18), and was drunk to obtain victory and power for the king. Next came that of Njörd and Frey, for peace and plenty. 'After that it was the custom of many to drink Bragi's full. Men also drank to those of their kinsmen who had been famous, and that was called minni.' It is possible that this account may be imperfect or inexact, as another passage mentions Thor as well as Odin in this connection. This is a story of how St. Martin appeared in a dream to King Olaf Tryggvason, and said to him: 'It has been the custom of men in this country, as well as elsewhere among heathen people, that ale is given to Thor and Odin, and toasts are assigned to the Æsir, when there is drinking or feasting in common.' The saint then suggests that in place of the old gods Olaf should substitute Martin himself, along with God and His saints. This was actually what took place in Norway and Iceland, a fact which shows how strong a hold on popular feeling the practice must have had. In the early Christian law of Norway it was enjoined that ale was to be brewed for certain festivals, such as All Hallowmas and Christmas, 'and that ale shall be consecrated to Christ and Saint Mary for peace and plenty.' Omission to do so was punishable by a fine to the bishop. In place of drinking to the heathen gods and their departed kinsmen, men now drank the minni of Christ, of Mary, of St. Martin, St. Olaf, or other saints, and even of the Holy Ghost, and this practice continued to be observed at wedding-feasts in Iceland as late as the seventeenth century.

The great festivals took place especially at three seasons in the year. One of these was at the close of autumn (about the middle of October) 'to greet the winter.' At mid-winter came the festival of Yule (Jól or Júl), originally held in the middle of January, but afterwards altered to correspond with Christmas. The third was held at the end of the winter (about the middle of April) 'to greet the summer.' The precise time of each, however, may have varied in different parts of Scandinavia; Adam of Bremen, for instance, represents the great Upsala festival as taking place about the spring equinox, while Snorri places it a little earlier. As late as 1020 these three festivals were still kept up by the majority of the inhabitants in the district of Thrandheim in Norway, and must have been maintained in Sweden for nearly a century later. The return which the worshippers hoped to obtain from the gods for the sacrifices offered was mainly good seasons, abundant crops, peaceful times, and victory in war if it arose. To some extent each festival appears to have had a special object, but the statements on this point are not quite in agreement with each other. No doubt the desires of the worshippers were expressed in formal prayers offered up by the one who presided over the sacrifices, but no specimen of these has been preserved. Adam of Bremen asserts that in the sacrifices at Upsala use was made of many incantations of an odious character, but of the precise nature of these there is no indication. The drinking of the various toasts was certainly accompanied by formal speeches, of which those used in Iceland at a later date are probably the Christianised representatives.

It is noteworthy that in most of the references to these great religious festivals there is no statement that the sacrifices were offered to any particular deity, the usual expression being simply 'to sacrifice for peace,' etc., or 'to the gods.' The same vagueness sometimes appears when more private offerings are mentioned; it is simply said that the person 'performed a great sacrifice.' It may naturally be assumed, however, that the deity appealed to would vary according to the boon desired, or the preferences of the worshipper. Adam of Bremen, in fact, states that in event of pestilence or famine the offering was made to Thor; in case of war it was given to Odin; while Frey was the recipient on the occasion of a wedding. The Swedes are also said to have sacrificed to Frey for peace and plenty, and Thorgrim in Iceland honoured the same god at the beginning of winter (p. 26). Earl Hákon's sacrifice to Odin has already been mentioned (p. 16), and is in agreement with Adam of Bremen's statement.

Among the ancient Scandinavians there was no distinct priestly caste. The duty of presiding over religious ceremonies, and of acting as custodian of sacred places, was attached to persons who had also temporal authority of a more or less extensive nature. Highest of all stood the king, on whose attitude towards the gods and their worship the prosperity of his people was believed largely to depend. Next to him came the earls, who in this as in other respects acted as the representatives of the king. Among the titles of honour given by the poets to both kings and earls are those of 'ruler' or 'guardian' of sanctuaries. Finally each district had its recognised religious head in one or other of its most prominent men, whose power as a chief was naturally augmented in no slight degree by his position as priest. The holder of this double office appears in the Icelandic writings under the name of goði (also hof-goði), a derivative of goð 'god(s)'; it may be assumed that the name was also known in Norway, and its existence in Denmark is certified by its occurrence in Runic inscriptions. The sagas contain numerous references to these priestly chiefs, who are sometimes named after the god whom they specially worshipped (as Freys-goði), sometimes after the place where they resided (as Tungu-goði), or after those whose religious head they were (as Ljósvetninga-goði). By the older constitution of Iceland the number of recognised goðar was thirty-nine, distributed pretty equally in the various parts of the island. The office itself was, at least in Iceland, known by the name of goð-orð, and was regarded as an item of personal property, which might even be shared by more than one person, so that we find such statements as 'he had a third of the goð-orð with Thorgeir.' The right to the office was hereditary, and could also be transferred by one person to another, and this was frequently done, especially when the rightful holder was to be absent from the country for a time. In one case the claimant to a goð-orð is described as performing a ceremony which may have been a usual accompaniment of such transference. He 'said, "we shall redden ourselves in the goði's blood in the old fashion," and killed a ram, in the blood of which he reddened his hands, and claimed Arnstein's goð-orð.' The goði being as much a chief as a priest, the name did not disappear with the adoption of Christianity into Iceland, though it naturally lost its religious associations and thenceforward denoted only the recognised leader in the various districts of the island.

It appears also that women to some extent acted as priestesses, and in Iceland, at least, these were designated by the name of gyðja, or hof-gyðja, a feminine form corresponding to goði and hof-goði. In one passage where a Thord Freys-goði is spoken of, a female relative of his is also mentioned as being hof-gyðja. When the missionary Thorvald was preaching Christianity at Hvamm in the west of Iceland about 984, a certain Fridgerd 'was meanwhile in the temple and performed sacrifice, and each of them could hear the other's words'; then Thorvald made a verse in which he gives the name of gyðja to Fridgerd. Other women are also mentioned with this appellation, but the precise place of the priestess, and her relation to the priest, remains somewhat obscure.

That the public worship of the gods was thus in the hands of the most prominent men in the community, and not merely of a separate priestly class, indicates that the Scandinavian peoples as a whole were really interested in their religion. This is also shown by the thoroughly popular character of the great sacrificial feasts. In earlier times it is probable that the belief in the native gods was strong even to a degree of fanaticism, of which traces are still found in the historic period, especially in Sweden and in the more northerly districts of Norway. The words of Gudbrand already quoted (p. 10) no doubt express a genuine religious attitude common to many worshippers of the Æsir, and similar confessions of faith are to be met with in other accounts. When King Hákon wished his subjects to adopt Christianity, 'and believe in one God, Christ the son of Mary, and abandon all sacrifices and the heathen gods,' there arose a great murmur in the assembly, and the speaker who replied protested against the idea 'that we should abandon that faith which our fathers have had before us ... and yet this faith has served us well.' Instances have already been given of the strong attachment which individuals had for certain gods, whom they regarded as their dear and faithful friends, consulted them in all their difficulties, and gave them joint-ownership of their possessions. Others again were zealous in erecting temples and maintaining sacrifices, such as Hall in Thorskafirth, who 'raised a great temple, because Ulf,' the chief man of the district, 'was no sacrificer.' By such men the encroachments of Christianity were naturally regarded with resentment and dismay. At the Althing in Iceland in 996 it was decided that any one blaspheming the gods should be prosecuted by a near kinsman, and for one to be a Christian was reputed a disgrace to all the kindred. Four years later, while the adoption of Christianity was being debated at the Althing, a volcanic eruption was reported from the neighbourhood, whereupon the heathens said, 'It is no wonder that the gods are angry at such talk.' In 1020 the men of Thrandheim held sacrifices after the old fashion, drinking to the gods, killing cattle and horses, and reddening the altars with the blood; this was done on account of a great dearth in that part of Norway, 'and it seemed clear to all men that the gods were angry because they had turned to Christianity.' So late as the twelfth century the people in some parts of Sweden were still inclined to throw off such Christianity as they had, and revert to the sacrificial rites of the old religion.

On the other hand, it is clear that even in the ninth and tenth centuries the worship of the Æsir was gradually losing its hold. Some of the early settlers in Iceland were either wholly or partly Christian; among the latter were, for example, Helgi the Lean, who believed in both Thor and Christ, and the kinsmen of the Hebridean Örlyg, who 'believed in Columcille, though they were not baptized.' A belief 'in their own might and strength' was all the faith that some of the Scandinavians of this period would own to. Many who came into intercourse with southern peoples accepted the prima signatio, or first sign of adoption into the Christian Church. From at least the beginning of the ninth century zealous missionary efforts were made by the Church to supplant Thor and his hammer by Christ and the cross; while, on the other hand, the Scandinavian religion, however strong its hold upon its adherents, never succeeded in spreading beyond its original limits. The combination of all these facts explains the comparatively rapid manner in which the old faith finally succumbed before the new, leaving behind it only the imperfect traces which have been summed up in these pages, and a mythology which has a profound interest of its own and is inextricably associated with the history of Old Norwegian and Icelandic poetry.