 Complete the following phrase:  After the assassination of Julius Caesar in 44 BC, the Ptolemaic Kingdom , which had ruled Egypt since the Wars of Alexander the Great brought an end to Achaemenid Egypt the Thirty-first Dynasty, took the side of Mark Antony in the last war of the Roman Republic, against the eventual victor Octavian, who as Augustus became the first Roman emperor in 27 BC, having defeated Mark Antony and the pharaoh, Cleopatra VII, at the naval 