Year 1275 (MCCLXXV) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. Events By place Byzantine Empire Battle of Neopatras: Emperor Michael VIII (Palaiologos) assembles a Byzantine expeditionary force (some 30,000 men), mostly mercenaries from Bulgaria, Serbia and the Sultanate of Rum. He places these forces under his own brother, John Palaiologos, and General Alexios Kaballarios. Michael sends them against Thessaly, and is supported by the Byzantine navy led by Admiral Alexios Doukas Philanthropenos, who is ordered to attack the Latin principalities and prevent them from aiding John I (Angelos), ruler of Thessaly. John is caught by surprise by the rapid advance of the Byzantine forces and is bottled up with a garrison in his capital of Neopatras, which the Byzantines proceed to lay siege. John manages to escape: he climbs down the walls of the fortress with a rope and walks through the Byzantine lines. After 3 days, John reaches Thebes, where he requests the aid of John I de la Roche, duke of Athens. He receives some 500 horsemen with whom he returns to Neopatras. Meanwhile, the Byzantine forces have been weakened, with several detachments sent off to capture other forts or plunder the region. The Byzantines panic under the sudden attack of a smaller but disciplined Latin force and breaks completely when a Cuman contingent switches sides. Despite John's attempt to rally his forces, they flee and scatter. Battle of Demetrias: Michael VIII (Palaiologos) sends a Byzantine fleet led by Alexios Philanthropenos, to harass the Latin coasts. A joint Latin fleet composed of Lombard and Venetian vessels from Negroponte (Euboea) and Venetian-held Crete, is variously given at 30 to 60 ships. The Latin fleet under Admiral Guglielmo II da Verona gets the Byzantines by surprise and their attack is so effective that they almost win. Their ships, on which high wooden towers have been erected, have the advantage, and many Byzantine seamen and soldiers are killed or drowned. Just as victory seem theirs, Greek reinforcements arrive, led by John I (Angelos). His arrival boosts the Byzantines' morale, and John's men, ferried on board the ships by small boats, begin to replenish their casualties and turn the tide. The Latin casualties are heavy, which also include Guglielmo. By nightfall, all but two Latin ships have been captured. Europe May 13 – Marinid forces led by Sultan Abu Yusuf Yaqub ibn