Re: Byzantium Emperor Alexius Comnenus " Why isn't he called "the great"?
Actually Manuel I was quite adept at diplomacy and his foreign policy wasn't wholly unsucessful. He reduced Hungary to a minor threat, allied himself with the HRE and reaffirmed the Roman Empire as the greatest power at the time. He also fostered good relations with the crusaders and the Crusader states. His foreign policy failed in his Italian campaign and in his campaigns against the Seljuqs.
The Italian campaign has always seemed as a waste of ressources to me and rather Manuel should have focused on defeating the Turks and reclaiming the last parts of Anatolia. As far as I know his popularity was decreased because of his Latin wife Mari who became a quite unpopular regent after his death and his fondness for Western ideals.
Still, it was Andronikos who destroyed the relations with the rest of the European states with his arrest of Latins in Constantinople. The Angeloi when they came to power, caused a revolt in Bulgaria by raising the tax levels and proving incapable of destroying the revolt afterwards. Under Alexios III the Empire's wealth was wasted on bribing the aristocracy and the army to remain loyal to the Emperor and the Bulgarians managed to conquer extensive territories alongside the Seljuqs who benefitted from the new internal problems of the Roman state. It was dynastic struggle between the Angeloi that was one of the main factors in bringing the Fourth Crusade to Constantinople