In his later years, Superbus faced significant opposition, causing his reign to be filled with conflict. Despite his authoritative rule as the seventh and last Roman king, his tyrannical actions led to insurrections among nobles, and ultimately, a rebellion spearheaded by Lucius Junius Brutus in 509 BC. This concluded with Superbus being overthrown and the establishment of the Roman Republic.
Following his dethronement, Superbus sought assistance from his son-in-law, Octavius Mamilius of Tusculum, and later from Lars Porsena, an Etruscan king. Despite his efforts to regain power, all attempts proved futile, leading to his retreat to Cumae, Campania.
In terms of demise, exact details are largely speculative due to the uncertain historicity of the era. However, most historical narratives agree he spent his final years in exile and died bitter and uninterrupted in Cumae. His death marked the definitive end of the Roman Kingdom, paving the way for the era of Roman Republic, where his legendary tyranny became a cautionary example for future Roman politicians.