He pursued Pompey to Alexandria, where Pompey was murdered by a former Roman officer serving in the court of King Ptolemy XIII. Caesar then became involved with the Alexandrine civil war between Ptolemy and his sister, wife, and co-regent queen, the Pharaoh Cleopatra VII. Perhaps as a result of Ptolemy's role in Pompey's murder, Caesar sided with Cleopatra; he is reported to have wept at the sight of Pompey's head, which was offered to him by Ptolemy's chamberlain Pothinus as a gift. In any event, Caesar withstood the Siege of Alexandria and latter he defeated the Ptolemaic forces in 47 BC in the Battle of the Nile and installed Cleopatra as ruler. Caesar and Cleopatra celebrated their victory of the Alexandrine civil war with a triumphant procession on the Nile in the spring of 47 B.C. The royal barge was accompanied by 400 additional ships, introducing Caesar to the luxurious lifestyle of the Egyptian pharaohs.