Battle of Demetrias The Battle of Demetrias was a sea engagement fought at Demetrias in Greece in the early 1270s between a Byzantine fleet and the assembled forces of the Latin barons of Euboea ( Negroponte ) and Crete . The battle was fierce , and initially in favour of the Latins , but the timely arrival of Byzantine reinforcements tipped the scale , resulting in a crushing Byzantine victory . Background . In the aftermath of the Fourth Crusade and the dissolution of the Byzantine Empire in 1204 , the Aegean Sea , once Byzantium ' s naval heartland , was dominated by a hodgepodge of Latin principalities , protected by the naval might of the Republic of Venice . Following the recapture of Constantinople and the restoration of the Byzantine Empire in 1261 , one of the chief priorities of Emperor Michael VIII Palaiologos ( ruled 1259 – 1282 ) was the defence of his capital from a Venetian attack . Consequently , he sought an alliance with Venice ' s major antagonist , the Republic of Genoa , while he began building up his own navy . With the aid of his newly - constructed fleet , in 1263 Palaiologos sent an expedition to the Morea , against the Principality of Achaia . At the verge of victory , the Byzantine land forces were surprised and defeated , while the joint Byzantine - Genoese fleet was dealt a severe blow by a numerically inferior Venetian fleet at the Battle of Settepozzi . This led to the abandonment of the Genoese alliance by Michael , who initiated a rapprochement with Venice , leading to a treaty in 1267 . With the neutralization of Venice , the major threat to imperial interests in the Aegean were the Lombard corsairs based at Negroponte . The island was repeatedly attacked by the Byzantine fleet under Alexios Philanthropenos , but no permanent gains were achieved . Only from 1273 , with the aid of the Latin renegade Licario , did Byzantine forces make headway , capturing a number of fortresses on the island . In the early 1270s ( the exact date is uncertain , most recent scholars favour 1272 / 1273 or 1274 / 1275 ) , Michael VIII Palaiologos launched a major campaign against John I Doukas , ruler of Thessaly . It was to be headed by his own brother , the " despotes " John Palaiologos . To prevent any aid coming to him from the Latin principalities , he also dispatched a fleet of 73 ships , headed by Philanthropenos , to harass their coasts . The Byzantine army , however , was defeated at the Battle of Neopatras with the aid of troops from the Duchy of Athens . At the news of this , the Latin lords took heart , and resolved to attack the Byzantine navy , anchored at the port of Demetrias . The battle . The opposing fleets ' numbers are unclear . For the Byzantines , Nikephoros Gregoras writes of " over 50 " vessels , while the Italian Marino Sanudo mentions 80 imperial ships . The joint Latin fleet , composed of Lombard and Venetian vessels from Negroponte and Venetian - held Crete , is variously given at 30 ( Gregoras ) to 62 ( Sanudo ) ships . At any rate , all sources confirm that the Latin fleet was numerically inferior by about a third . Pursuant to their truce with the Byzantines , the Venetians of Negroponte themselves maintained an officially neutral stance , although some of their number did join the Latin fleet as individuals . The Latin fleet caught the Byzantines by surprise , and their initial attack was so violent that they made good progress . Their ships , on which high wooden towers had been erected had the advantage , and many Byzantine seamen and soldiers were killed or drowned . Just as victory seemed within the Latins ' grasp , however , reinforcements arrived led by the " despotes " John Palaiologos . While retreating from Neopatras , the " despotes " had learned of the impending battle . Gathering whatever men he could , he rowed forty miles in one night and reached Demetrias just as the Byzantine fleet was beginning to waver . His arrival boosted the Byzantines ' morale , and Palaiologos ' s men , ferried on board the ships by small boats , began to replenish their casualties and turn the tide . The battle continued all day , but by nightfall , all but two Latin ships had been captured . The Latin casualties were heavy , and included the triarch of Negroponte Guglielmo II da Verona . Many other nobles were captured , including the Venetian Fillippo Sanudo , who was probably the fleet ' s overall commander . Aftermath . The victory at Demetrias did go a long way to mitigating the disaster of Neopatras for the Byzantines . It also marked the beginning of a sustained offensive across the Aegean : by 1278 , Licario had subdued all of Euboea except for its capital , Chalkis , and by 1280 , as grand admiral ( " megas doux " ) of the Byzantine navy , he had retaken most of the Aegean islands for the Empire . His achievements were not to last long after his disappearance from history in c . 1280 , however . In Euboea , Licario ' s major gain and personal fief , the Byzantine forts were gradually retaken by the Lombards , until they recovered the entire island by 1296 .