In the West the Bishop of Rome was recognized as having superiority over the other Patriarchs, while in the East, the Patriarch of Constantinople gradually came to occupy a leading position. In the East the Pope was generally considered first among equals, but not a direct superior.. The sees of Rome and Constantinople were often at odds with one another, just as the Greek and Latin Churches as a whole were often at odds both politically and in things ecclesiastical. There were complex cultural currents underlying these difficulties, including the fact that in the West feudal models began to influence the way of viewing relations within the Church. The tensions led in 1054 to a serious rupture between the Greek East and Latin West called the East-West schism, which while not in many places absolute, still dominates the ecclesiastical landscape.
In 1204, the Fourth Crusade invaded, seized and sacked Constantinople, and established the Latin Empire. This was not the doing of the Bishop of Rome, the Pope. Initially he spoke out against the fourth crusade. In writing to his legate the pope said, in part "How, indeed, is the Greek church to be brought back into ecclesiastical union and to a devotion for the Apostolic See when she has been beset with so many afflictions and persecutions that she sees in the Latins only an example of perdition and the works of darkness, so that she now, and with reason, detests the Latins more than dogs?"
However the popes accepted the acts of the accompanying Latin clergy who set up a Latin Patriarchate subservient in the Western manner to the Pope. The pope recognised these "Latin" sees at the Fourth Council of the Lateran. Furthermore those Orthodox bishops left in their place were made to swear an oath of allegiance to the pope.
When the last Latin emperor Baldwin II fled from Constantinople he was well received in Rome by Pope Urban IV who promised him support to regain the throne. This threat of continued support prompted the new Greek emperor to seek out a reunion. Understanding the situation of 1204 helps with the context of the reunion council.
By establishing communion with the Latin Patriarchs the Papacy in effect made official their position within the Roman Catholic Church. This act was part of a more general picture in which the Crusaders on the one hand established Latin Kingdoms officially acknowledged by the Roman Catholic Church, in the Middle East and in Greece and the Greek Islands, and also in parts of the Balkans. Included were a similar array of Latin episcopal sees. The Latin Empire in Constantinople was eventually defeated and dispossessed by a resurgent Byzantium in 1261, although the Latin Patriarchate persisted as a titular office with varying vigour, based in Rome at the St. Peter's Basilica.
For a time, like many ecclesiastical offices in the West, it had rival contenders who were supporters or protégés of the rival popes. As to the title Latin Patriarch of Constantinople, this was the case at least from 1378 to 1423. Thereafter the office continued as an honorific title, during the later centuries attributed to a leading clergyman in Rome, until it ceased to be assigned after 1948 and was finally abolished in 1964.
Phillips, J., (2009) Holy Warriors: A Modern History of the Crusades (Vintage Books; London), p195.
Pope Innocent III - To Peter, Cardinal Priest of the Title of St. Marcellus, Legate of the Apostolic See. However, on the way to attack Constantinople the crusaders attacked another Christian city, Zara, and received papal absolution for this. de Villehardouin, G., (1908) Memoirs or Chronicle of The Fourth Crusade and The Conquest of Constantinople (J.M. Dent; London), p26.
Styled by Catholics as the Twelfth Ecumenical Council.
Papadakis, A., (1994) The Christian East and the Rise of the Papacy, (St Vladimir’s Seminary Press; Crestwood, NY), p204.
Herrin, J., (2007) Byzantium: The Surprising Life of a Medieval Empire (Princeton University Press; Princeton, NJ), pp. 300–1.
Wolff, Robert Lee (1954). Politics in the Latin Patriarchate of Constantinople, 1204-1261. Dumbarton Oaks Papers, Vol. 8. Dumbarton Oaks, Trustees for Harvard University. pp. 225–303. (JSTOR)
Hazlitt, W. Carew (1860). History of the Venetian republic: her rise, her greatness, and her civilisation, Vol. IV.. London: Smith, Elder and Co., 65, Cornhill. p. Chapter 22. Contarini was at the Council of Constance in November 1414.
Giorgio Fedalto, La Chiesa latina in Oriente, Mazziana, Verona, 2nd ed. 1981, e vol.
Loenertz, R.-J. (1966). "Cardinale Morosini et Paul Paléologue Tagaris, patriarches, et Antoine Ballester, vicaire du Papae, dans le patriarcat de Constantinople (1332-34 et 1380-87)". Revue des études byzantines (in French) 24: 224–256. doi:10.3406/rebyz.1966.1373.
List of Latin Patriarchs of Constantinople by GCatholic.org