The history of the first church of Ales, dedicated to Santa Maria di Monserrato, is closely linked to that of its village, with which it shares its origin. If the town, a village of shepherds and peasants with a small cemetery, had not already existed, the bishop of Usellus would never have been able to take refuge there around the year 1150, according to Mons. Tomasi. It initially became a provisional cathedral, only to pass the title four centuries later to the larger church dedicated to St. Peter the Apostle. Originally built in the Pisan style in the 12th century, it now has a late Renaissance façade. St. Mary's consists of a portal, a small bell gable placed at the side and a single nave. Inside, according to Msgr. Tomasi, the walls around the altar had a stone plinth with the function of a seat, which traditionally served the canons in ancient times. Over the past 30 years, it has undergone numerous renovations that have led to the addition of a sacristy within the walls of the old, now demolished cemetery. Worthy of note is the small statue of St Mary, which is rich in devotional signs, restored from fire damage. The feast of Santa Maria di Monserrato is celebrated on 7 and 9 September, an event that attracts the entire Marmilla region.