Today, 29 September is Michaelmas Day, one of the four traditional quarter days in the year. They are Lady Day (25th March), Midsummer (24th June), Michaelmas (29th September) and Christmas (25th December). As these were the days when rent was due perhaps they were days your ancestors saw approach with dread.
Starting a few days later were the Michaelmas term, the beginning of the legal and academic years.
Michaelmas was traditionally marked by feasting on a goose. Read about that and more, something for each day of the year, in Chamber's Book of Days (1869 version).