Roman Republic replaced by Roman Empire
Constitutional system
The constitutional history of the Roman Republic began with the revolution which overthrew the monarchy in 509 BC, and ended with constitutional reforms that transformed the Republic into what would effectively be the Roman Empire, in 27 BC. The constitution of the Roman Republic was a constantly-evolving, unwritten set of guidelines and principles passed down mainly through precedent, by which the government and its politics operated.
substituted by superseded by succeeded by followed by replaced with