Catholic Encyclopedia (1913)/Lateran Councils
A series of five important councils held at Rome from the twelfth to the sixteen century. From the reign of Constantine the Great until the removal of the papal Court to Avignon, the Lateran palace and basilica served the bishops of Rome as residence and cathedral. During this long period the popes had occasion to convoke a number of general councils, and for this purpose they made choice of cities so situated as to reduce as much as possible the inconveniences which the bishops called to such assemblies must necessarily experience by reason of long and costly absence from their sees. Five of these councils were held in the Lateran palace, and are known as the First (1123), Second (1139), Third (1179), Fourth (1215), and Fifth Lateran Councils.
Other, non-ecumenical councils were held at the Lateran, among the best known being those in 649 against the Monothelite heresy, in 823, 864, 900, 1102, 1105, 1110, 1111, 1112, and 1116. In 1725, Benedict XIII called to the Lateran the bishops directly dependent on Rome as their metropolitan see, i.e. archbishops without suffragans, bishops immediately subject to the Holy See, and abbots exercising quasi-episcopal jurisdiction. Seven sessions were held between 15 April and 29 May, and various regulations were promulgated concerning the duties of bishops and other pastors, concerning residence, ordinations, and the periods for the holding of synods. The chief objects were the suppression of Jansenism and the solemn confirmation of the Bull "Unigenitus," which was declared a rule of faith demanding the fullest obedience.