close ties with the Latin states of southern Greece in an attempt to maintain their independence, while at the same time being threatened by them and forced to cede territory to them. Both were eventually reunified under the Byzantines in the 1330s and the Serbians shortly after. From his capital at Neopatras, John I Doukas governed Thessaly as a virtually independent state. Although he recognized the suzerainty of the Byzantine emperor Michael VIII Palaiologos (), receiving the title of sebastokrator in exchange, John I Doukas maintained a consistent anti-Palaiologan stance. In this conflict he allied himself with Latin powers, namely Charles of Anjou and the Duchy of Athens. Michael VIII's attempts to form a union of the Orthodox and Catholic Churches, culminating in the Second Council of Lyon in 1274, were another point of friction. John portrayed himself as a champion of Orthodoxy, offering refuge to pro-Unionists and convoking a synod at his capital Neopatras in 1276/7 to condemn the Union. Sometime in 1273–75 (the date is disputed by scholars) Michael VIII dispatched a large army against John under his own brother, John Palaiologos. The Byzantine army advanced rapidly through Thessaly and blockaded John with a few of his men at Neopatras, which was placed under siege. John managed to evade the Byzantines and secure aid from Athens, with which he routed the Byzantine army at the Battle of Neopatras. In exchange for this aid, however, John gave his daughter Helena to the future Duke of Athens William de la Roche (), with the towns of Zetounion, Gardiki, Gravia, and Siderokastron as a dowry. In addition, the fleeing Byzantine troops were able to reach Demetrias and help their fleet secure a devastating victory against the Lombard lords of Euboea. A further Byzantine expedition in 1277 against John was equally unsuccessful. Finally, in 1282 Michael VIII in person campaigned against John, but fell ill and died on the way. Nevertheless, after John's death, his widow was compelled to recognize the suzerainty of Michael VIII's successor, Andronikos II Palaiologos () to safeguard the position of her underage sons Constantine and Theodore. Thus the Byzantines were allowed passage through Thessaly to invade Epirus in 1290, but soon after the two princes started conspiring with the Serbians of King Milutin against Byzantium. In 1295 the brothers invaded Epirus themselves and seized Naupaktos, but no further gains appear to have been made. Both Constantine and