 Despite these reverses , in early 1261 , Emperor Michael VIII set his sights on capturing the great prize : Constantinople , the capital of the Byzantine Empire , which had been the seat of the Latin Empire since its capture by the Fourth Crusade in 1204 . To this end , Michael concluded an alliance with Genoa in March , and in July 1261 , as the one @-@ year truce concluded after the previous failed Nicaean attack was nearing its end , Strategopoulos , recently released from Epirote custody , was sent with a small advance force of 800 soldiers ( most of them Cumans ) to keep a watch on the Bulgarians and spy out the defences of the Latins . 
