Piazza Ventidio Basso is named after Publio Ventidio Basso, a Roman politician from the I century BC, who was a native of Ascoli. The square is a wide irregular space, known in the Late Middle Ages as Platea Inferior or Sancti Anastasii as opposed to the Platea Superior (Piazza del Popolo). Every year, the costumed figures from all the sestieri –the ancient name for city quarters- gather in this square to start the historical parade of the Quintana jousting tournament.

The Church of Santi Vincenzo and Anastasio, the Church of San Pietro Martire, a medieval house, several renaissance buildings and noble towers face onto the square.

The Church of Santi Vincenzo e Anastasio, whose present shape dates back to XIV century, was erected in the XI century on a pre-existing hypogeal temple from the VI century, whose original design featured a quadrangular base and detached belfry. It is among the oldest Romanesque churches of the town; its façade is divided into 64 panels, once frescoed and framed.

The Church of San Pietro Martire is the most successful example of local Gothic art. The construction of the church began around 1280, about 20 years after the construction of the church of San Francesco, and finished in the first half of the XV century. San Pietro Martire is one of Ascoli’s four basilicas, along with the Cathedral, San Francesco and Sant’Agostino.