been promised financial and military aid by Isaac's son Alexios IV, with which they had planned to continue to Jerusalem. When the crusaders reached Constantinople, the situation quickly turned volatile, and while Isaac and Alexios briefly ruled, the crusaders did not receive the payment they had hoped for. In April 1204, they captured and plundered the city's enormous wealth.

The crusaders selected their own emperor from among their own ranks, Baldwin IX of Flanders,