The citizens of Constantinople rebelled in late January 1204, and in the chaos an otherwise obscure nobleman named Nicholas Kanabos was acclaimed emperor, though he was unwilling to accept the crown. The two co-emperors barricaded themselves in the Palace of Blachernae and entrusted Mourtzouphlos with a mission to seek help from the crusaders, or at least they informed him of their intentions. Instead of contacting the crusaders, Mourtzouphlos, on the night of 28–29 January 1204, used his access to the palace to bribe the "ax-bearers" (the Varangian Guard), and with their backing arrest the emperors. The support of the Varangians seems to have been of major importance in the success of the coup, though Mourtzouphlos also had help from his relations and associates. The young Alexios IV was eventually strangled in prison; while his father Isaac, both enfeebled and blind, died at around the time of the coup, his death variously attributed to fright, sorrow, or mistreatment. Kanabos was initially spared and offered an office under Alexios V, but he refused both this and a further summons from the emperor and took sanctuary in the Hagia Sophia; he was forcibly removed and killed on the steps of the cathedral.