CONCLAVE (Fr., Sp., Port., It., Lat., room which may be locked, from com-, together + clavis, key, Gk. κλείς, kleis, key, from κλεῖν, klein, to shut). Either the place where the cardinals assemble for the choice of a pope, or the assembly itself. In 1179 a Lateran Council decreed in its first canon that a two-thirds vote of the cardinals was essential for a choice. This decree was developed; and the regulations which are, substantially, still in force established by Gregory X. at the Council of Lyons in 1274. These rules are intended to provide against unnecessary delay or precipitation in election, and against any external interference with absolute freedom of choice. The large hall is divided into a number of small apartments, two rooms being allotted to an ordinary cardinal and three to one of princely rank. People are allowed to enter freely during the first day, at the end of which all entrances are absolutely closed except one, which remains under the strict supervision of officials designated for the purpose. Food and other necessaries are handed through a window, and are subjected to a rigorous examination, in order to prevent communication with the outer world, the cardinals not being allowed to leave the place, or to receive or send out letters, until a new pope is chosen. Consult: Zöpffel, Die Papstwahlen (Göttingen, 1871); for a more popular treatment, Trollope, The Papal Conclaves, as They Were and as They Are (London, 1876). A full and graphic description of a typical conclave, that which elected Alexander VII., will be found in Shorthouse, John Inglesant (London, 1881). See Pope.