What were the cultural beliefs and events during the middle ages that would have impacted Chaucer's writing?

The primary cultural belief was in the supremacy and power
of the Church. The common belief in Chaucer's time was that life was merely a state
preceding when one went to an eternal reward or punishment. It was also widely believed
that the Church held the keys to heaven and hell and could ordain that one go to either
place at its will. The very essence of the Canterbury Tales
indicates this: The travellers were on a pilgrimage to Canterbury to pray at the tomb of
Thomas Becket, a Saint of the Church. It was widely believed that pilgrimages were a
form of penance that would atone for sin. The fact that several of the travellers were
in church related orders is also indicative. Although Chaucer indicates that some were
less than holy, in fact, some such as the Pardoner are absolute crooks. This may not
have been true in fact, but there was the widespread belief that churchmen were by and
large as sinful as the next person.