 Complete the following phrase:  After the outbreak of the Greek War of Independence in March 1821, the Greeks besieged the fortress for several months. The garrison surrendered in the first week of August 1821 after being assured of safe passage, but were all massacred. The fortress remained in Greek hands until captured by Ibrahim Pasha of Egypt on 11 May 1825. The Ottoman-Egyptian garrison remained in the fortress until it was handed over to the 