Among the highest expressions of Gothic architecture of the region and northern Italy, which probably dates back to V-VI century. Present building is the result of a conglomeration of earlier structures of episcopal area, whose materials were reused for new church. Among these buildings it is still visible St. John's Church, used with baptismal function. Towards the year 1070 the building collapsed. In 1095 new Cathedral was consecrated by Pope Urban II and later took further reconstruction, according to massive project. The three-nave Cathedral is linear Gothic style, with predominance of verticality expressed by pointed arches. At the beginning of the fourteenth century Cathedral was enriched with a great side portal in Gothic style. The facade has three rosettes topped by two oculi and a cruise box. Romanesque bell tower dates back to 1266, it contains nine bells and was remodeled in the eighteenth century. In 1470, as a result of beautification campaign funded by Pelletta family it was placed marble statue of Assumption surrounded by six heads of winged angels, dominates the square of Cathedral and oversee the city. Always the celebrations for Patron saint were great and varied, with stages to accommodate singers and musicians coming from other cities. Inside it is decorated with important works of art from Asti.