What's the noun for jubiles? Here's the word you're looking for.
jubilee
(Jewish historical) A special year of emancipation supposed to be kept every fifty years, when farming was abandoned and Hebrew slaves were set free. [from 14th c.]
A 25th, 40th, 50th, 60th or 70th anniversary. [from 14th c.]
(Catholicism) A special year (originally held every hundred years, then fifty, and then fewer) in which remission from sin could be granted as well as indulgences upon making a pilgrimage to Rome. [from 15th c.]