Final answer:
Octavian, the adopted son and heir of Julius Caesar, formed the Second Triumvirate with Marc Antony and Lepidus after Caesar's assassination. This alliance defeated Caesar's assassins and paved the way for the end of the Roman Republic and the establishment of the Roman Empire under Octavian's rule.
Step-by-step explanation:
The question references the period after Julius Caesar's assassination on the Ides of March in 44 BCE and relates to the subsequent political developments in ancient Rome. When Caesar was assassinated, Octavian, his adopted son and heir, was outside of Rome. Octavian, who is also known as Augustus later in his life, leveraged his position as Caesar's heir to secure the loyalty of Caesar's military veterans and the political support necessary to rise to power.
In 43 BCE, Octavian formed the Second Triumvirate with Marc Antony and Lepidus to share dictatorial powers. This powerful alliance was sanctioned by the Roman Senate and effectively operated as a legal entity. Their combined forces successfully battled the assassins of Caesar at the Battle of Philippi and carried out punitive measures against their political adversaries. The Second Triumvirate eventually led to the end of the Roman Republic and the rise of the Roman Empire with Octavian at its helm.