In Scandinavia, Vetrnætr or "Winter Nights" occurred in three or more days in mid-October, being celebrated in Iceland between October 11-18 (Ellis-Davidson, Myths and Symbols, p. 39). This was the celebration of the start of winter. [...]
The feasts and celebrations associated with Vetrnætr were termed vetrnátta blót, "the winter night sacrifice" (Cleasby-Vigfússon, p. 701 s.v. vetr). The celebrations would have probably included an animal sacrifice (blót), with communal feasting after the sacrificed animal had been cooked. Hákonar saga Góða chapter 17 mentions specifically that a horse was sacrificed for the vetrnátta blót, and cooked in a kettle. Perhaps the most important part of the Vetrnætr celebration would have been the ceremonial drinking of ale, or sumbel, which was preserved even into Christian times. In chapter 17 of Hákonar saga Góða, the Vetrnætr sumbel is described:
Um haustið að vetri var blótveisla á Hlöðum og sótti þar til konungur.... En er hið fyrsta full var skenkt þá mælti Sigurður jarl fyrir og signaði Óðni og drakk af horninu til konungs.
[In fall, at the beginning of winter, there was a sacrificial feast at Hlaðir and the king attended it.... Jarl Sigurðr proposed a toast, dedicating the horn to Óðinn, and drank to the king.] (Heimskringla, pp. 110).
With the advent of Christianity, the old pagan celebrations were co-opted and reinvested with Christian overtones. In the case of Winter Nights, it appears that the celebration was shifted to November 1, All Saints' Day, for the Gulaþing Law records that all Gulaþing farmers were required, in groups of at least three, to brew ale and hold a party for peace and prosperity after consecrating the drink to Christ and St. Mary
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