On Monday 30 November 1215 in the Basilica of St John Lateran, Innocent III brought the first assembly of the whole Church since the Council of Chalcedon (451) to a rousing finale by summoning all the delegates to unite in faith and by issuing Ad Liberandam, an encyclical calling for a crusade to liberate the Holy Land. This Council, fourth in the Lateran series but the twelfth ecumenical gathering of the Church in the Western tradition, included the five patriarchs or their representatives, together with more than one thousand bishops, abbots and other dignitaries, both ecclesiastical and secular. At each of the three plenary sessions held on 11, 20 and 30 November respectively, Innocent preached a set-piece sermon whilst, behind the scenes, delegates debated such major issues as who was more worthy to lead the Empire and how to contain the Albigensian heresy.
The accounts of eyewitnesses reveal that Innocent’s consecration of Santa Maria in Trastevere and celebrations for the anniversary of the dedication of the Vatican Basilica served not only to emphasize the history, majesty and ritual of the Church but also offered a welcome respite from the intensive discussions in the Lateran Palace. The Fathers of the Council promulgated seventy decrees, covering topics as diverse as heresy, Jewish-Christian relations, pastoral care and Trinitarian theology as well as ecclesiastical governance. Monks and secular clergy were to be reformed, the nascent mendicant orders welcomed to the Church and diocesan bishops instructed to implement far-reaching conciliar decisions across Christendom.
Eight hundred years on, Lateran IV still stands as the high-water mark of the medieval papacy, its political and ecclesiastical decisions enduring down to the Council of Trent whilst modern historiography has deemed it the most significant papal assembly of the Later Middle Ages.
In November 2015, we have a unique opportunity to re-evaluate the role of this Council in the reform of the universal Church, during an international Congress performed from 23 to 29 with a rich programme.
Taking an inter-disciplinary approach, we shall investigate how its decisions affected the intellectual, cultural, social and religious life of the medieval world.