Construction of the cathedral (founded 1612) began in 1621 following plans by Andrés de Espinoza and continued for several decades under the architect Moscoso; it was completed under Juan de Aldana in 1656. Following a fire in 1844 and the 1868 earthquake it was rebuilt by Lucas Poblete, and it retains much of the original plan. It is a long, low building, with a façade occupying the entire north end of the city’s main square, the Plaza de Armas. It is divided into three largely undecorated registers, each incorporating a series of 70 columns. Surrounding the Plaza de Armas are two-storey Neo-classical arcades built in sillar (a white, porous volcanic stone), which complement the cathedral and give the square a sense of architectural unity. The second storey (post-1900) was added in the Republican period.