Jubilee

A Jubilee is a celebration of a particular anniversary of an event, usually denoting the 25th, 40th, 50th, 60th, and 70th anniversary. It originated from the Hebrew Bible, specifically from the laws concerning the Sabbatical year and the Jubilee year, which involved freeing of debt slaves and recognizing that all property belongs to God. The term was adopted by Roman emperors to celebrate their reigns, and later by monarchs to denote the celebrations associated with their rule after a milestone number of years have passed.learn more on wikipedia