The Fourth Lateran Council meets, defining the doctrine of transubstantiation, the process by which bread and wine are, by that doctrine, said to transform into the body and blood of Christ.

The Fourth Council of the Lateran or Lateran IV was convoked by Pope Innocent III in April 1213 and opened at the Lateran Palace in Rome on 11 November 1215. Due to the great length of time between the Council's convocation and meeting, many bishops had the opportunity to attend what is considered by the Catholic Church to have been the twelfth ecumenical council.