Santa Maria Maggiore, Vasto

However, documentary evidence dates only to 1195 in a document from Henry VI Hohenstaufen, Holy Roman Emperor sent to Odorisio, the abbot of the Benedictine monastery of the San Giovanni in Venere Abbey in Fossacesia, confirming that abbeys possession of the church of Sacte Marie in Guastoaymonis.

There was apparently a burst of construction in the 13th and 14th century, including rebuilding a tall bell-tower, which also served as a defensive fortification, in what was an Adriatic town prone to Saracen raids.

On August 1, 1566, the Ottoman admiral Piali Pasha, sacked the town and burned all the churches.

The crypt holds in a glass case relics (bones and blood) of the first (or 4th) century Christian martyr, St Cesario, donated by don Cesare Michelangelo d'Avalos.

This relic was donated by Pope Pius IV (1499 – 1565) to Francesco Ferdinando d’Avalos, a prominent commander and statesman in the employ of the Hapsburgs of Spain.