Some people say the Republic ended with the naval Battle of Actium between Marcus Antonius and Octavian. They both had been in the Second Triumvirate. It was fought on 2 September 31 BC. Octavian won. Later on, he was proclaimed Roman Emperor. The end date could also be when Octavian was given the title of the first "Augustus" by the Senate. This was on 16 January 27 BC.