The Fourth Lateran Council, convened by Pope Innocent III, begins in Rome. on November 11, 1215. It was a significant event in the history of the Catholic Church, attended by over 400 bishops and 800 abbots.
Significant outcomes included the formal introduction of the term transubstantiation to describe the Eucharist, the mandate for annual confession and Easter communion, and the development of procedures that led to the Inquisition.