I've never once done a Roman TL before. The PoD for this one is that Marcus Antonius doesn't meet Cleopatra until around 35 BC. This is only a draft version of it, so please go easy on me.
This alternate timeline diverges from our own in the year 41 BC (712 AUC). Marcus Antonius (more famously known as Mark Antony) travels to Judea to quell yet another rebellion in that rebellious Roman province. In OTL, Marcus Antonius meets the Egyptian Queen Cleopatra VII in Tarsos. The point of divergence in this timeline is that Marcus Antonius and Cleopatra do not meet, and thus, do not become lovers.
This has little immediate effects on the history of the world at first. Fulvia, Antonius’s wife, still rebels against Octavianus when he divorces Fulvia’s daughter, Clodia. Fulvia is captured, and exiled to Sicyon, where she died of a sudden illness while waiting for her husband Antonius. With Antonius a widower, Octavianus and Antonius strengthened their triumvirate in 40 BC (713 AUC) when Octavianus allows his half-sister, Octavia, to marry Antonius.
In 38 BC (715 AUC), a Sicilian revolt lead by Sextus Pompeius forced Octavianus to keep Antonius’s promised army in Italy to crush the revolt. Antonius had planned to conquer the Parthians. This lead to a quarrel in the triumvirate, and at Tarentum, the triumvirate was renewed for another five years.
Antonius didn’t have the necessary supplies to conquer the Parthians, and thought that Octavianus didn’t support the cause. In our history, Antonius went to Cleopatra for aid. She gave it to him, but the army was defeated. In Rome, Marcus Aemilis Lepidus (the third member of the triumvirate) resigned after a poor political move, leaving only Antonius and Octavianus as members of the triumvirate.
Lepidus was accused of usurping power in Sicily, and he and his supporters were exiled in 36 BC (717 AUC).
Antonius, in 37 BC (716 AUC), traveled to Egypt to find support for his Parthian campaign, leaving behind Octavia pregnant in Rome. Antonius settled in Alexandria for one year, and after Lepidus’s exile, Octavianus accused Antonius of going native, a heinous crime in Rome.
Antonius’s popularity spiraled the longer he lived in Egypt. In 35 BC (718 AUC)-at the urging of Octavianus-Octavia divorced her husband, and her child, Gauis Octavianus Agrippa Vipsanius, was adopted by Octavianus as his heir (due to butterflies, Tiberius Claudius Nero Caesar died at an early age). Antonius, in response, married an Egyptian woman.
Antonius met Cleopatra and Caesarion (the illegitimate child of Julius Caesar) in 33 BC (720 AUC) at a party in Alexandria. Antonius was surprised to discover that Caesarion was the child of Julius Caesar, and thus, the true heir to the great Caesar. Antonius fell in love with Cleopatra, and wanted to marry her. Antonius’s Egyptian wife died, and Antonius married Cleopatra. After his marriage, Antonius and Octavianus attempted to rebuild the triumvirate, but failed due to Cleopatra’s interference.
Cleopatra and Antonius now planed to invade Rome and place Caesarion as the dictator of Rome in place of Octavianus. News reached Rome quickly about Cleopatra and Antonius. Word also reached Octavianus (now the sole consul of Rome and the supreme dictator) that Antonius planed to capture Rome, and place Caesarion in Octavianus’s spot as dictator.
Preemptively, in 31 BC (722 AUC), Octavianus sent an army and fleet under Agrippa to Egypt to capture Cleopatra, Antonius, and Caesarion. Agrippa’s fleet captured several pro-Egyptian ports along the western Mediterranean all through 31 BC, and in 30 BC, arrived at Alexandria.
Agrippa destroyed the Egyptian fleet a few miles north of Alexandria at the Battle of the Nile, where Antonius was captured. Antonius was shipped back to Rome. Sailing to Alexandria, Agrippa landed his soldiers on the outskirts of the city, and they began to advance. They set up a siege.
Antonius arrived in Rome on the Ides of March in 30 BC (723 AUC). Antonius was taken before Octavianus in chains and naked. He was paraded around Rome several times like a triumph before arriving before Octavianus. Octavianus ordered that Antonius be crucified for his crimes, and the Senate agreed. Days later, Antonius committed suicide before the sentence could be carried out.
In Alexandria, Cleopatra and Caesarion were trapped. Months after the siege began a ship from Rome arrived at Alexandria. Octavianus Agrippa Vipsanius, the nephew of Octavianus and the heir to Octavianus, was to become the Pharaoh of Egypt, a client king of Rome. Agrippa would in turn become the heir to Octavianus.
Alexandria finally fell in the first month of 29 BC (724 AUC). When Roman troops stormed the palace, Cleopatra and Caesarion were dead. Vipsanius was crowned the Pharaoh of Egypt as Pharaoh Vipsanius, and Agrippa stayed behind for a year to cleanup and pacify Egypt.