Here is a neat article about Lammas.
http://www.schooloftheseasons.com/lammas.html The year is 1100. The date is August 1. The monks in the abbey at Gloucester are celebrating the holy-day of St. Peter in Chains. One of the monks wakes from a strange dream in which God promises to strike down the wicked King who has abused the Holy Church. His superior, Abbot Serlo, on hearing of the dreams sends a warning to the King, William the Red, who has oppressed all of England with taxes and disgusted many with his licentiousness and blasphemy. Red, as he is called, receives the message the following day while preparing to indulge in one of his favorite sports, hunting, in the New Forest. Although there are no longer any people dwelling in the New Forest — they were all cleared out by Red's father, William the Conqueror — there are rumors that it's a hotbed of pagan activity. And August 2 is an important pagan holy-day. The Saxons call it Lammas, the Loaf-Mass. William the Red laughs at the warning from the monks and goes out hunting. A short time later, he is dead, struck in the chest by a stray arrow, and his brother, Henry, who was in the hunting party is riding hot-foot for Winchester and the crown.
Now some people say that William the Red was a Lammas sacrifice, that having made a wasteland of his kingdom, he was killed by the people (or the Gods) as a sacrifice to bring new life to the land. And some people say his brother Henry has him assassinated. And some people say that both versions are true.
~more