There’s a lot of interesting background about the history of this council which was both religious and political. Check it at Fourth Lateran Council, Papal Encyclicals Online.
When the council began in the Lateran basilica in November 1215 there were present 404 bishops from throughout the western church, and from the Latin eastern church a large number of abbots, canons and representatives of the secular power. No Greeks were present, even those invited, except the patriarch of the Maronites and a legate of the patriarch of Alexandria. The bond with the Greek church was indeed neglected, and matters became more serious through the actions of Latin bishops living in the east or through the decrees of the council.