In 1262 the Earl, Rolando Palatino, built the church dedicating it to Saint Margaret. Its 14th century portal and rose window can be observed today on its façade. As can be read on a headstone situated in the lunette of the portal, this was done by Ruggero de Fragenis in 1293.
Later on, the whole building was transformed into a monastery and the church was dedicated to Saint Augustine. According to the scheme of the churches of the Mendicant orders of the 13th-14th centuries, the church had to have only one nave with a trussed ceiling and vault apses. The belfry tower was rebuilt in the 13th century; nevertheless it kept its basic medieval style, recognizable in the big lancet arch.
Once the Augustinian community was dissolved, in 1808 the monastery was assigned as a military quarter and the church was declared a Collegiate Church and dedicated to Saint Joseph, from the name of the king reigning at the time.
In 1824, the enlargement of the church was designed and different successive modifications followed up to the beginning of the 20th century, when a new church with a baptistery was built.
The interior, with an only nave, remade in gothic style between 1890 and the 1920s, presents a valuable covering with wall paintings in neo-medieval style, with the typical bi-chromatic feature of the faux ashlars of painted stone, achieved by the Florentine artist, Achille Carnevale, in 1923.
The Cathedral of Vasto keeps several sacred art works, heritage of the Augustinian Fathers’presence in the city. The transept of the church keeps a beautiful and old statue, still covered with colorful and showy fabric clothes, of the "Madonna della Cintura", of the Neapolitan artistic school, which came directly from Naples thanks to the good intercession of the Augustinian Fathers, and placed in a wooden well-carved niche in Gothic style. On the main altar there is the polyptych portraying “The Redemptor among angels”, dating to 1369.
In recent times the wooden furnishings, frames, books, plaster and wrought-iron handiworks, crucifixes, sculptures, oleographs, ex-voto offerings and even the apses of the Augustinian church of the year 1200 discovered in the cellars of the Cathedral, became part of an exhibition set up in the Cathedral itself.