On April 12, 1204, during the siege of Constantinople, Emperor Alexios V Doukas Mourtzouphlos set his headquarters near the Monastery. From this vantage point he could see the Venetian fleet under command of Doge Enrico Dandolo deploying between the monastery of the Euergetes and the church of St. Mary of the Blachernae before attacking the city. After the successful attack he took flight abandoning his purple tent on the spot, and so allowing Baldwin of Flanders to spend his victory night inside it. The complex was sacked by the crusaders, and afterward it was assigned to Benedictine monks of San Giorgio Maggiore. During the Latin occupation of Constantinople (1204–1261) the building became a Roman Catholic church.