I would go back even farther, all the way to the end of the Second Punic War. Scipio Africanus was the one who expanded the practice of client-patron relationships to a geopolitical scale to build an independent power base. He was also the innovator of the cults of personality that would become common. He never tried to overthrow the republic, but some of the political practices used to destabilize the late republic can be traced back to his innovations.