his son, John VIII. In September 1423, Thessalonika was surrendered to the Venetians, no doubt hoping to draw in the Western Powers into a new crusade and, if not, at least their wealth would enable them to defend it. In February 1424, Manuel II Palaiologos re-established Byzantium as a vassal of the Ottomans — 300,000 silver coins were to be paid to the Sultan on annual basis. That the Empire managed to accomplish this at its lowest ebb is remarkable. Nonetheless until the 1450s, the Ottomans would not make any concerted efforts to overcome the walls of Constantinople, and the city retained a tenuous security for the next two decades. John VIII takes over Manuel II's final years saw his gains wasted and the Empire status quo ante 1391. John VIII was still hopeful that he could emulate his Father's success and more. Like his predecessors, his attempts were in vain. And just like his predecessors, he relied too heavily on a Pope not willing to give, but only take; take that is, the Church of a wretched state surrounded by the Ottomans, soon-to-be Christendom's direst foe. Union with Rome Uniting the Church of Byzantium with that of Rome was a simple matter, since all the bargaining chips were in the hands of the Roman Catholic West. John VIII, as the de facto head of the Byzantine Church ordered the Byzantine Church to accept Papal primacy and declared that the Filioque dispute arose from semantic confusion. Few on Byzantium's side were impressed with the Union between 1438 and 1439 held in Ferrara and Florence, not only at the terms at which the Byzantine Church had to stoop to, but also at the non-existent aid to Byzantium. One can safely say that the most notable effect of the Union was the increased resentment between Byzantium's populace and the Imperial government. Varna In the late 1440s, the Ottomans experienced difficulty in bringing their Christian vassals in the Balkans into line. Hungary began launching successful campaigns against the Turks in Serbia, leading to the Serbian Despot and the Albanian resistance leader George Kastrioti Skanderbeg into direct opposition with their former masters. This led to one of the last great Crusades of a united Western Christendom — Crusade of Varna. Murad II was in no position to stop these troublesome westerners since he was overwhelmed with problems by easterners in Anatolia, the core of