The Latin Patriarch of Constantinople was one of the four Roman Catholic "patriarchs of the east". He was not the same person as the "Patriarch of Constantinople".
Before the Great Schism in 1054, the church was ruled by five patriarchs, who sat in Rome, Constantinople, Jerusalem, Alexandria, and Antioch. The Patriarch of Rome was the one to whom the highest honors were accorded, and that of Constantinople was second. The Patriarch of Rome held that that meant the other four patriarchs (and so, indirectly, all Christians) owed him obedience. The other four patriarchs did not accept that position, and because of that and other differences, the Eastern and Western churches separated in 1054, becoming what we now know as the Roman Catholic Church and the Eastern Orthodox Church.
In 1204 the fourth Crusade invaded, seized and sacked Constantinople, and established the Latin Empire. They brought with them Roman Catholic ecclesiatics, who set up a Latin Patriarchate loyal to the Pope. The Latin establishment was defeated and dispossessed in 1261, although the Latin Patriarchate persisted, based at St. Peter's Basilica in Rome, until 1506.
List of Latin Patriarchs of Constantinople
(Constantinople retaken in 1261; Patriarchate now titular only)