Back in the Medieval Ages, people in England were required to be part of the Catholic Church. The pope was the leader of the medieval English church.
In November, the Medieval English people celebrated what we today call Halloween; they would stay up into the night drinking, eating, and remembering their dead loved ones.
Another festival, named Twelfth Night, was the celebration of the magi going to Nazareth and meeting baby Jesus. They celebrated this event in the month of January.
Other festivals celebrated in the Middle Ages were St Valentine's Day (February), Easter (March), Christmas (December), etc.
The core beliefs of the medieval English church were that Jesus died on the cross for their sins, but that they still needed to do all sorts of rituals and good deeds to get into heaven.
The Good News in fact is that God so loved the world, that He gave his only-begotten Son, that whosoever believes in Him should not perish, but have everlasting life (The Bible, John 3:16). That means that we do not need to perform good works to have everlasting life, but to believe in Jesus for the forgiveness of our sins. However, because we love God, we do good works; they are a fruit of our obedience to God.