The church of St. Ambrose, patron saint of Monserrato, has undergone several changes over time. The original facility, dating back to the sec. XV – XVI in late Catalan Gothic style, had a crenellated horizontal finial, the winged buttresses, and the archiacute portal with overleaf and central oculus. In 1615 the two side arms with access doors to the cemetery were assembled. In 1619 the bell tower was erected, which collapsed in 1848, devastating part of the facade. Since 1890 the elevation has had a gabled facade and a bell tower in the 19th-century style. The single longitudinal nave is punctuated by ogival arches supported by small polyform capitals. The pointed barrel vault is traversed by ogival sub-arches. The presbytery chapel is the original part of the building. The ogee-shaped triumphal arch leading to the chancel is surmounted by a Gothic fretwork cross, and the shelf on the right is carved with the coat of arms of the Sanjusti family to whom Villa Pauli was granted as a fief in 1426.
