The temple burned in 83 BCE during civil unrest and was rebuilt by Sulla, then burned again in 69 CE, deliberately, during the fighting between the emperor Vitellius and the forces backing Vespasian, an act ancient writers treated as a particular sacrilege precisely because it targeted the state's most sacred building.
Vespasian and then his son Domitian rebuilt it a final time, on a still grander scale, and it stood into late antiquity before Christianization and the general decline of traditional Roman cult left it to slow ruin and, eventually, quarrying for building stone, so that almost nothing of the ancient temple remains visible above ground today.
The hill's second life began in the Italian Renaissance, when Pope Paul III commissioned Michelangelo to redesign its summit as the Piazza del Campidoglio, the trapezoidal civic square, ringed by palazzi and centered on a bronze equestrian statue, that still crowns the hill and today houses Rome's city government and the Capitoline Museums. That civic reuse, layered directly over the vanished religious one, is also why capitol, by way of the Capitoline's name, became the generic English word for a legislative building on a height, most famously the United States Capitol in Washington, itself named in conscious reference to Rome's ancient hill rather than to any surviving structure on it.