The Square rose up on the ancient Roman Forum and since the 1st century B.C. had represented the political, religious, economic and cultural centre of the town. Within a steep slope frame, the Roman architects achieved a rectangular platform on top of the hill, surrounded by the most important public and religious buildings. The modern town still preserves its ancient balance. The religious power is represented by the Cathedral and the annexed Palazzo Vescovile (Bishop’s Palace), on the Northern side of the Square, contrasting with the three lay Municipal palaces, built between the 12th and the 13th centuries: Palazzo del Popolo, Palazzo del Capitano and Palazzo dei Priori. Probably, in ancient times, the Square must have covered a larger area up to embracing the modern annexed Piazza Garibaldi which shields the ruins of an ancient Roman Basilica (the Nicchioni). The architectural complexity of the area is shown by the huge quantity of underground tunnels unfolding underground the same square, as evidence of historical and structural layering perfectly joining together over time.