The final session of the Lateran Council, convened to rectify abuses in the papal electoral process that had led to the elevation of the antipopes Constantine II and Philip, was held in Rome. Lateran Council (769): The Lateran Council of 769 was a synod held in the Basilica of St. John Lateran to rectify perceived abuses in the papal electoral process which had led to the elevation of the antipopes Constantine II and Philip. It also condemned the rulings of the Council of Hieria. It is perhaps the most important Roman council held during the 8th century. April 15, 769. Wiki link