John Palaiologos ( brother of Michael VIII ) John Doukas Palaiologos ( , 1225 / 1230 – 1274 ) was a Byzantine aristocrat , brother to Emperor Michael VIII Palaiologos ( r . 1259 – 1282 ) , who served as the commander - in - chief of the Byzantine army . He played a prominent part in his brother ' s military campaigns , most notably in the crucial victory at the Battle of Pelagonia , but also in repeated campaigns against Epirus and against the Turks in Asia Minor . He retired from active service after his defeat at Neopatras , and died shortly after . Biography . Early life and first successes . John Doukas Palaiologos was born sometime after 1225 , the son of Andronikos Palaiologos , the " megas domestikos " of the Empire of Nicaea , and his first wife Theodora Palaiologina . John was their second son , after the future emperor Michael Palaiologos , and the fourth child overall . Nothing is known of him until 1256 , when he appears to have been sent to Rhodes ; the reasons for this , i . e . whether this was to take charge of a military or administrative post or as an exile , are unknown . He appears again in 1258 , when he participated in the coup launched by his elder brother Michael Palaiologos , then " megas konostaulos " , against the regent for the underage John IV Laskaris ( r . 1258 – 1261 ) , George Mouzalon . After Mouzalon ' s murder , Michael placed the young emperor under the protection of John and their half - brother Constantine . Michael quickly secured his own nomination as regent , and in turn appointed John as " megas domestikos " and sent him to command the Nicaean army in Macedonia , with Alexios Strategopoulos and John Raoul Petraliphas as subordinate commanders . After his coronation as co - emperor in early 1259 , Michael raised his brother further to the rank of " sebastokrator " ( Strategopoulos succeeded him as " megas domestikos " ) , and arranged a marriage to a daughter of the general Constantine Tornikes . Michael then ordered John to attack Michael II , the ruler of the rival Byzantine Greek state of Epirus . The Nicaean army advanced so quickly that they caught the Epirote army by surprise at its camp at Kastoria , and forced it to flee in disorder . John then proceeded to retake the fortresses of Deabolis and Ochrid , only recently captured by the Epirotes . The cities fell after short sieges , and the plain of Pelagonia , with the town of Bitola , and around Lake Prespa , was subjugated . Michael of Epirus , however , marshalled his forces , and was reinforced with men from the Principality of Achaea and the Latin states of southern Greece under Prince William II of Villehardouin himself , as well as a Sicilian contingent . Further forces were provided by Michael II ' s bastard son , John Doukas , ruler of Thessaly . The allied force was clearly superior in numbers to the Nicaean army , and John Palaiologos avoided direct confrontation , instead using his mobile Turkish and Cuman horse archers to wear down the opposing forces . In addition , the allied army was divided by conflicting aims and the hatred between the Epirote Greeks and the Latins . A quarrel with William II led to the withdrawal of the Epirote army and the temporary defection of John Doukas to the Nicaean camp . The next day , the Nicaean forces attacked the Latins and secured a crushing victory ; William II himself and many other barons were taken prisoner , while most of the Latin soldiery was killed or captured . In the aftermath of this success , joined by the forces of John Doukas , John Palaiologos marched south into Thessaly , seizing and fortifying its fortresses , until he reached the town of Neopatras , where he made his camp for a time . He then continued on into Boeotia , the territory of the Duchy of Athens , where he took and plundered Levadeia and Thebes . At this point , however , John Doukas defected back to his father , upsetting the balance of power and John himself was soon after recalled to Lampsacus . Thus , his conquest of Greece remained incomplete and was soon reversed by the recovery of Epirus ' fortunes . Later years and death . At Lampsacus , John met with his brother , who rewarded his victories with the title of " despotes " , the second after the emperor himself in the Byzantine hierarchy , while his father - in - law Tornikes and his half - brother Constantine were raised to " sebastokratores " . Then , or sometime after , he was also given the islands of Rhodes and Lesbos as personal domains ( " pronoia i " ) . In July 1261 , Constantinople was recovered and the Byzantine Empire restored with Michael VIII as sole emperor . In the meantime , however , things had been going badly in Epirus , where Michael II had recovered his realm and was once again threatening imperial possessions in Macedonia . In 1261 , John was sent on campaign against the Epirotes . After long and hard fighting , in the summer of 1263 / 1264 he achieved a major victory , which forced Michael II to come to terms : the Epirote ruler acknowledged imperial suzerainty , and his son and heir , Nikephoros , was married to Anna Kantakouzene , a niece of Michael VIII . After this success , he was sent to Asia Minor , where the Turkish raids on the Byzantine borderlands had become a menace , and where Turkish settlers had begun encroaching upon imperial territory . He remained there until 1267 and achieved some success , securing the lands around the valley of the Maeander River and restoring the defences of the region . The historian George Pachymeres certainly praised his conduct of these operations , and alleged that the mere mention of his approach caused fear to his enemies . In the late 1260s , John returned to Europe , and there is evidence of his activity in Macedonia and Thessaly . He had estates in the valley of the river Strymon in Macedonia , and is attested in documents concerning the properties of monasteries in eastern Thessaly , which the Byzantines had probably recovered by that time , following the death of Michael II of Epirus in 1267 / 1268 . John Doukas of Thessaly , however , remained one of the Empire ' s chief opponents , and Michael Palaiologos organized a campaign ( variously dated to 1272 / 1273 or 1274 / 1275 ) to finally subdue him . It was a large - scale undertaking : an army of some 30 , 000 men , mostly mercenaries , was placed under the command of John Palaiologos and Alexios Kaballarios , while the land forces were to be aided by a fleet of over 70 vessels under Alexios Philanthropenos . The campaign was initially crowned with success , as the Byzantine army advanced quickly through Thessaly and besieged John Doukas at his capital Neopatras . The latter , however , was able to escape in secret , procure aid from the Duchy of Athens , and utterly defeat the besieging Byzantine army at the Battle of Neopatras . With his forces scattered , John Palaiologos retreated to the north ; on his way , he learned of an attack by the Latin fleet on the Byzantine navy at Demetrias . Assembling whatever men he could find , the " despotes " led his troops in a forty - mile ride , through the night , towards Demetrias . There they encountered the battle in full swing , and the Latins having the advantage . The arrival of fresh troops , however , tilted the balance , and the battle ended in a crushing Byzantine victory . Despite his contribution to the victory at Demetrias , John Palaiologos was shattered by the loss of his army at Neopatras . According to the Byzantine sources , he resigned his title of " despotes " ( although some modern historians have postulated that it was revoked by his brother ) , and appears to have died shortly after ( 1273 / 1274 or 1274 / 1275 , depending on the dating of the Thessalian campaign ) .