the first council of the Western Church held in the Lateran Palace in 1123; focused on church discipline and made plans to recover the Holy Lands from the Muslim 'infidels'
the Lateran Council in 1215 was the most important council of the Middle Ages; issued a creed against Albigensianism, published reformatory decrees, promulgated the doctrine of transubstantiation, and clarified church doctrine on the Trinity and Incarnation