History of the East–West Schism
Disunion in the Roman Empire further contributed to disunion in the Church. The Emperor Diocletian famously divided the administration of the eastern and western portions of the Empire in the early 4th century, though subsequent leaders (including Constantine) aspired to and sometimes gained control of both regions. Theodosius the Great, who established Nicene Christianity as the official religion of the Roman Empire (see Edict of Thessalonica), was the last Emperor to rule over a united Roman Empire. Following his death in 395, the division into western and eastern halves, each for a few decades still under its own Emperor, was never reunited.
Final War of the Roman Republic
Cleopatra did not immediately follow Antony in suicide. Instead, in a last-ditch effort, Cleopatra opened negotiations with Octavian. Cleopatra begged Octavian to spare Caesarion’s life in exchange for willing imprisonment. Octavian refused. Within a week, Octavian informed Cleopatra that she was to play a role in Octavian's Triumph back in Rome. This role was "carefully explained to her", while Caesarion was "butchered without compunction". Octavian supposedly said "two Caesars are one too many" as he ordered Caesarion's death. According to Strabo who was alive at the time of the event, Cleopatra died from a self-induced bite from a venomous snake, or from applying a poisonous ointment to herself. Learning of Cleopatra's death, Octavian had mixed feelings. He admired the bravery of Cleopatra, and gave her and Antony a public military funeral in Rome. As they left Alexandria, a new age dawned when Rome annexed Egypt. With Cleopatra's death, the final war of the Republic was over.
Within a month, Octavian was named Pharaoh, and Egypt became his personal possession. By executing Antony's supporters, Octavian finally brought a century of civil war to a close. In 27 BC Octavian was named Augustus by the Senate and given unprecedented powers. Octavian, now Augustus, transformed the Republic into the Roman Empire, ruling it as the first Roman emperor.