: Augustus became the first emperor in 27 BC, marking the end of the Roman Republic and the start of centuries of imperial rule.
: By 117 AD under Emperor Trajan, the empire reached its peak, stretching from Britain to Egypt and Iberia to Mesopotamia. Roman Empire
: Plagued by invasions and economic crises, the Western Roman Empire collapsed in 476 AD when the last emperor, Romulus Augustulus, was deposed. : Augustus became the first emperor in 27