The area was inhabited since Roman times, but the town only dates back to the ninth century when the population sought refuge in fortresses on the hills to escape the Saracens.
During the Middle Ages it followed the historical events of nearby Sora, with many landowners in succession. In 1229 the town was destroyed in retaliation by Frederick II in the fight against the pope. It was later ruled by various illustrious families, including the D’Avalos, the Della Rovere, and the Ludovisi Boncompagni.
For a time there was a cenobitic (common good) community of Celestine V followers who left valuable sacred objects, now preserved in the town church.
The name is composed of “pesco” (meaning, in this case, overhanging cliffs or hilly elevations) and “solid” (hard). Repeatedly struck by earthquakes (1349, 1654 and 1775) and completely destroyed by that of January 1915, including the old castle already turned into a palace, the town was subsequently rebuilt outside the ancient walls; while on the rocky outcrop on which it was first perched remain only some ruins. There were many victims.
Earlier, after the unification of Italy, it has been part of the phenomenon of banditry. At the same time large-scale emigration began. In the second world war the town had significant losses.