third lateran council: the Lateran Council in 1179 that condemned the heresies of the Albigenses and the Waldenses
council: (Christianity) an assembly of theologians and bishops and other representatives of different churches or dioceses that is convened to regulate matters of discipline or doctrine
julian calendar: the solar calendar introduced in Rome in 46 b.c. by Julius Caesar and slightly modified by Augustus, establishing the 12-month year of 365 days with each 4th year having 366 days and the months having 31 or 30 days except for February