The validity of the Western legates' act is doubtful because Pope Leo died and Cerularius' excommunication only applied to the legates personally. Still, the Church split along doctrinal, theological, linguistic, political, and geographical lines, and the fundamental breach has never been healed, with each side sometimes accusing the other of falling into heresy and initiating the division. The decades-long Norman conquest of southern Italy and Sicily by Robert Guiscard that began in 1061, the Latin-led Crusades, the Crusade of 1101, the Massacre of the Latins in 1182, the West's retaliation in the Sacking of Thessalonica in 1185, the capture and pillaging of Constantinople during the Fourth Crusade in 1204, and the imposition of Latin patriarchs made reconciliation more difficult. Establishing Latin hierarchies in the Crusader states meant that there were two rival claimants to each of the patriarchal sees of Antioch, Constantinople, and Jerusalem, making the existence of schism clear. Several attempts at reconciliation did not bear fruit.