Passage: In the spring of 1087, news reached the Byzantine court of a huge invasion from the north. The invaders were Pechenegs from the north west Black Sea region; it was reported that they numbered 80,000 men in all. Taking advantage of the precarious situation of the Byzantines, the Pecheneg horde headed towards the Byzantine capital at Constantinople, plundering the northern Balkans as they went. The invasion posed a serious threat to Alexios' Empire, yet due to years of civil war and neglect the Byzantine military was unable to provide the emperor with enough troops to repel the Pecheneg invaders. Alexios was forced to rely on his own ingenuity and diplomatic skill to save his empire from annihilation. He appealed to another nomadic tribe, the Cumans, to join him in battle against the Pechenegs.

Question: Where is the capital of Byzantine
Constantinople