You might remember the Parthians. This is now the Parthian Persian Empire. They're the successors of the Seleucids, or the successor of Alexander the Great, who was the successor in Persia of the Achaemenid Empire. And while fighting the Parthians, he is killed. Crassus is killed while fighting the Parthians, which breaks up this first triumvirate, and then Pompey switches sides. He switches sides over to the conservative side. So now, instead of being one of Julius Caesar's allies, he becomes one of his opponents.