In 1648 Brunengo started building one of two planned towers, but it collapsed on April 29, 1683, for reasons never discovered, and in its fall almost completely destroyed the rest of the church.

Construction of the present cathedral was begun in 1687 to plans drawn up by the architect Domenico Spotorno, who had died on June 17, 1684, in Ales and was later buried in the new building.

The new cathedral was completed after the death of Spotorno by the architect Ignatius Merigano, with the help of the master builders Antonio Cuccuru and Lucifero Marceddu of Cagliari.

The west front, with a curved top, is framed by two bell towers, connected by a terrace equipped with a tufa balustrade, beneath which is a portico with a round arch.

The chapels and apse are barrel-vaulted, as are the nave and the transept, except of course at the crossing, which is roofed by the large octagonal dome (36 metres high), covered with decorations (1950-1962) and frescoes (1954), the more recent work by Peppinetto Boi Ales.