The Catholic Encyclopedia notes the historically obscure resignations of Pontian (230–235) and Marcellinus (296–308,) the historically postulated resignation of Liberius (352–366,) and one catalogue of popes lists John XVIII as resigning office in 1009.

The first historically unquestionable papal resignation is that of Benedict IX in 1045.  In order to rid the Church of the scandalous Benedict, Gregory VI gave Benedict "valuable possessions" to resign the papacy in his favor.  Gregory himself resigned in 1046 because the arrangement he had entered into with Benedict was considered simony.  Benedict IX was a pip, having been the first outwardly homosexual pope (elected at age 20) and the only one to serve as pope more than once (3 times.)  read the resignations including the conditional one made by Pius XII and John Paul II.  What is it with these Gregorys and Benedicts?