There had been several lengthy vacancies of the Holy See, most recently the "sede vacante" that had lasted from the death of Clement IV, 29 November 1268, until Gregory's election, 1 September 1271. The council decided that in future the cardinals should not leave the conclave until they had elected a pope. This decision was suspended in 1276 by Pope Adrian V, and then revoked by Pope John XXI. It has since been re-established, and is the basis of present legislation on papal elections.