When crimson leaves fell to the mud, the gods did thirst for human blood…
By way of a Celtic mythology page on Facebook, I found this information about Hallowtide. The festival has different names in different parts of the Celtic-speaking world. In Ireland it is known as Samhain and in Scotland as Samhuinn and in Man as Sauin (all 3 meaning “summer’s end”) In Wales it is Calan Gaeaf and in Breizh it is known as Kala-Goañv, meaning “calends of winter.” In Cornwall, it is Allantide.
Hallowtide marked the end of the leafy half of the year and beginning of the time of bare boughs. At this time it was easier to see prey in the forested chases and the antlered stag seemed to be an animal embodiment of the bare boughs of the winter. It was a time to appease the shadowy powers with offerings.
Though the sacrificial victim had come to be regarded as an offering to the powers of blight, he may once have represented a divinity of growth or, in earlier times, the corn-spirit. Such a victim was slain at harvest, and harvest is often late in northern Celtic regions, while the slaying was sometimes connected not with the harvest field, but with the later threshing. This would bring it near the Samhain festival.
The slaying of the corn-spirit was derived from the earlier slaying of a tree or vegetation-spirit embodied in a tree and also in a human or animal victim. The corn-spirit was embodied in the last sheaf cut as well as in an animal or human being. This human victim may have been regarded as a king, since in late popular custom a mock king is chosen at winter festivals.
In other cases the effigy of a saint is hung up and carried round the different houses, part of the dress being left at each. The saint has probably succeeded to the traditional ritual of the divine victim. The primitive period in which the corn-spirit was regarded as female, with a woman as her human representative, is also recalled in folk-custom. The last sheaf is called the Maiden or the Mother, while, as in Northamptonshire, girls choose a queen on St. Catharine’s day, November 26th, and in some Christmas pageants “Yule’s wife,” as well as Yule, is present, corresponding to the May queen of the summer festival.
Men also masqueraded as women at the Calends. The dates of these survivals may be explained by that dislocation of the Samhain festival already pointed out. This view of the Samhain human sacrifices is supported by the Irish offerings to the Fomorians–gods of growth, later regarded as gods of blight, and to Cromm Cruaich, in both cases at Samhain. With the evolution of religious thought, the slain victim came to be regarded as an offering to evil powers.