After Caesars assassination Cleopatra looked for a new ally in Rome and found General Mark Antony. After their first meeting they decided that they both needed something form the other and became allies. Antony went back to Egypt with Cleopatra even though he was married to Octavia, in that same year Cleopatra bore their twin sons, Alexander Helios and Cleopatra Selene. They were separated for four years after that.
Both the Egyptian and Roman Empires were furious about the elicit relationship between Cleopatra and Mark Antony. Augustus Caesar allied with the Egyptians to get rid of the "problem". When they were surrounded Cleopatra and Antony committed suicide by a snake bite.