▁V , ▁supported ▁by ▁Ven et ian ▁and ▁Ser bian ▁troops , ▁launched ▁an ▁attack ▁on ▁Matthew ▁Kant ak ou zen os . ▁John ▁Kant ak ou zen os ▁came ▁to ▁his ▁son ' s ▁aid ▁with ▁ 1 0 , 0 0 0 ▁Ott oman ▁troops ▁who ▁re to ok ▁the ▁cities ▁of ▁Th race , ▁liber ally ▁pl und ering ▁them ▁in ▁the ▁process . ▁In ▁October ▁ 1 3 5 2 , ▁at ▁Dem ot ika , ▁the ▁Ott oman ▁force ▁met ▁and ▁defeated ▁ 4 , 0 0 0 ▁Ser bs ▁provided ▁to ▁John ▁V ▁by ▁D ush an . ▁This ▁was ▁the ▁Ott om ans ' ▁first ▁victory ▁in ▁Europe ▁and ▁an ▁o min ous ▁port ent . ▁Two ▁years ▁later ▁their ▁capture ▁of ▁Gal lip oli ▁marked ▁the ▁beginning ▁of ▁the ▁Ott oman ▁con quest ▁of ▁the ▁B alk ans , ▁cul min ating ▁a ▁century ▁later ▁in ▁the ▁Fall ▁of ▁Constantin ople . ▁Meanwhile , ▁John ▁V ▁fled ▁to ▁the ▁island ▁of ▁T ened os , ▁from ▁where ▁he ▁made ▁an ▁un success ful ▁attempt ▁to ▁se ize ▁Constantin ople ▁in ▁March ▁ 1 3 5 3 . ▁▁ ▁John ▁VI ▁Kant ak ou zen os ▁respond ed ▁by ▁having ▁Matthew ▁crown ed ▁as ▁co - em peror , ▁but ▁John ▁V ▁Pal ai olog os , ▁en list ing ▁Gen o ese ▁support ▁and ▁re lying ▁on ▁the ▁decl ining ▁popular ity ▁of ▁Kant ak ou zen os , ▁succeeded ▁in ▁entering ▁the ▁capital ▁in