The Crusades were meant to be a united religious attempt to reliberate important Christian kingdoms while also to limit the spread and power of their main opposing, the Caliphates and later the Ottomans.

And as time went by, the attempts to liberate these cities were less successful than desired and even led to other disasters like the Battle of Zara and the attack of Constantinople which were both Christian cities.

Given that this was a divide between powers that were both Christian and did not want to allow the Islam force to spread as the Byzantine Empire was slowly losing its influence and strength as time went on, where there any attempts of either the Roman Catholic church, or the Orthodox Church to unite the two Churches after the East-West Schism in an attempt to unify against a common threat?