Marc Antony was a roman politician and was a general (80-83 BC). He was a great ally of Julius Caesar but the main enemy of Augustus(Octavian). He had a romantic and political relationship to Cleopatra, but backstabbed him in the end and was the reason for his downfall. But, After Caesar's death, he was in line to take control , but he lost control because Octavian took the throne by using force and his great army to overthrow Antony.
Caesar's death brought a chaotic control for power. ( see bottom paragraph for more information) Marc Antony was busy trying to find Caesar's killers while Octavian armies won many wars against Antony. Because of these wars, Marc was forced to retreat into Southern Gaul. This is when he formed a romantic and political relationship with Cleopatra. Cleopatra agreed to send forces to help protect eastern Rome from Octavian's grab. Octavian was using propaganda against Marc by saying that he left his wife for Cleopatra. In their last war, Marc’s army was defeated and he fled back to Cleopatra. When Octavian's forces invaded Egypt, they found Marc dead by suicide by his own sword and they captured Egypt.
When he was Caesar's second in command after he helped him defeat multiple enemies, he took control of Italy. He had great power to veto laws and make them. As a result, Caesar took him out of his position because he was a bad leader. After Caesar died, Antony gained everything and kept everything for himself even though the will called for the funds to go to public works. Octavian, his foe used his own funds to finish constructions and improve the cities, giving him public support over Antony. Soon Octavian became a senator and wanted to gain more power. Even though Octavian and Antony as a good relationship, they still wanted power over each other. This caused wars to break out, eventually making Antony lose everything. This is when he fled back to Egypt to Cleopatra.