In the Roman Catholic church, the assembly of cardinals gathered to elect a new pope and the system of strict seclusion to which they submit. From 1059 the election became the responsibility of the cardinals. When, after the death of Clement IV (1268), the cardinals dithered for more than two years, the local magistrate locked them in the episcopal palace and fed them only bread and water until they elected Gregory X. The system of meeting in closed conclave was codified in 1904 by Pius X. Voting is by secret ballot; one ballot is held on the first afternoon of the conclave and four on each subsequent day, two in the morning and two in the afternoon, until a new pope is chosen. In 1996 John Paul II declared that, after 30 ballots, the traditional requirement of a two-thirds majority plus one for the election of a pope could be superseded, at the discretion of the cardinals, by election by a simple majority. Ballots are burned in a stove after each vote, and the smoke produced by their burning, which issues from a special pipe through a window, indicates to the crowd assembled in St. Peter's Square whether a new pope has been elected: if there is a new pope, the smoke will be white; if no majority has yet been reached, the smoke will be black. In addition, bells will be rung to confirm the signal. Additives are mixed with the ballots to ensure the proper colour of the smoke.