Lex Titia
The Lex Titia was a Roman law passed on November 27, 43 BC, that legalized the Second Triumvirate of Octavian, Mark Antony, and Marcus Aemilius Lepidus. The Lex Titia gave this "three-man commission for restoring the constitution of the republic" (triumviri rei publicae constituendae) the power to make or annul laws without approval from either the Senate or the people; insulated their judicial decisions from appeal, and allowed the Triumvirs to name magistrates at will. Although the constitutional machinery of the Republic was not irrevocably dismantled by the Lex Titia, in the event it never recovered. Lepidus was sidelined early in the triumvirate, and Antony was eliminated in civil war, leaving Octavian the sole leader.
The passing of the Lex Titia marked the de jure end of the Roman Republic, though in practice it had already been almost completely subverted by the contending parties in the civil war that was then beginning. The law, ostensibly only a temporary measure, was renewed in 38 BC, but quarrels between Octavian and Antony after the downfall of Lepidus in 36 BC prevented the law from being further extended, leading to the expiration of the Lex Titia in 33 BC and the ensuing Final War of the Roman Republic.