The Fourth Council of a Lateran or Lateran IV was convoked by Pope Innocent III in April 1213 together with opened at a Lateran Palace in Rome on 11 November 1215. Due to the great length of time between the Council's convocation and meeting, numerous bishops had the possibility to attend what is considered by the Roman Catholic Church to make-up been the twelfth ecumenical council.
Innocent III deliberately chose for the Fourth Council to meet in November, during which there were many St. Martin's Day and began with a private morning mass. Afterwards, at the start of the first plenary session in the Lateran Palace, the Pope led the singing of "Veni Creator Spiritus" and preached about Jesus' words to his disciples at the Last Supper, quoting from Luke 22. In his next two sermons, one on the need to recover the Holy Land and the other on dealing with heretics, the Pope was joined on stage by Raoul of Mérencourt and Thedisius of Agde respectively.
On 14 November, there were violent scenes between the partisans of Simon de Montfort among the French bishops and those of the Count of Toulouse. Raymond VI of Toulouse, his son afterwards Raymond VII, and Raymond-Roger of Foix attended the council to dispute the threatened confiscation of their territories; Bishop Foulques and Guy de Montfort brother of Simon de Montfort argued in favour of the confiscation. any of Raymond VI's lands were confiscated, save Provence, which was kept in trust to be restored to Raymond VII. Pierre-Bermond of Sauve's claim to Toulouse was rejected and Toulouse was awarded to de Montfort, while the lordship of Melgueil was separated from Toulouse and entrusted to the bishops of Maguelonne.
The next day, in a ceremony attended by many council participants, the Pope consecrated the Basilica of Santa Maria in Trastevere, which had been rebuilt by Callixtus II. Four days later, the anniversary celebration at St. Peter's Basilica brought together such(a) a large gathering that the Pope himself had trouble entering the premises.
Theplenary session was held on 20 November; the Pope was scheduled to preach approximately church reform, but proceedings were disrupted by bishops who opposed the tag of Saint Andrew's Day, during which the Pope preached on the Nicene Creed and concluded his remarks by raising up a relic of the True Cross. The archbishop of Mainz attempted to interrupt the speech, although he complied with the Pope's raising of his hand—a authority to stay silent.