A papal renunciation (Latin: renuntiatio) occurs when the reigning pope of the Roman Catholic Church voluntarily steps down from his position. As the reign of the pope has conventionally been from election until death, papal renunciation is an uncommon event. Before the 21st century, only five popes unambiguously resigned with historical certainty, all between the 10th and 15th centuries. Additionally, there are disputed claims of four popes having resigned, dating from the 3rd to the 11th centuries; a fifth disputed case may have involved an antipope.
Additionally, a few popes during the saeculum obscurum were "deposed", meaning driven from office by force. The history and canonical question here is complicated; generally, the official Vatican list of popes seems to recognize such "depositions" as valid renunciations if the pope acquiesced, but not if he did not. The later development of canon law has been in favor of papal supremacy, leaving no recourse to the removal of a pope involuntarily.
The most recent pope to resign was Benedict XVI, who vacated the Holy See on 28 February 2013 at 19:00 UTC. He was the first pope to do so since Gregory XII in 1415.
Despite its common usage in discussion of papal renunciations, the term "abdication" is not used in the official documents of the Church for renunciation by a pope.
The 1983 Code of Canon Law mentions papal renunciation in Canon 332, where it states:
If it happens that the Roman Pontiff resigns his office, it is required for validity that the resignation is made freely and properly manifested but not that it is accepted by anyone.
This corresponds to Canon 221 of the 1917 Code of Canon Law,
If it happens that the Roman Pontiff resigns his office, it is not required for validity that the resignation is accepted by the Cardinals or by anyone else.