The site of Gualter has been known since ancient times, having been ceded to the monastery of Ripoll by Count Wilfred the Hairy, who would have occupied it before 890. In the 11th century, Ermengol IV of Urgell (Count between 1065 and 1092) intervened so that Ripoll would found a priory in the church of Santa Maria de Gualter and for this purpose he made several donations of goods and benefits in this territory.

In 1069 or 1079 (the date is uncertain) the counts of Urgell (Ermengol IV and his wife Llúcia de la Marca) endowed the monastery of Gualter in what is considered the foundation of this monastic house. It is known that in 1086 Ramon was its prior. In 1207 the bishop of Urgell, Pere de Puigverd, the abbot of Ripoll and other ecclesiastical authorities consecrated the church of the priory of Santa Maria de Gualter. The counts of Urgell, especially Ermengol VIII, continued to favour the monastery, which accumulated a large patrimony, although it never became more than a small priory, with only a prior, four monks and a few priests.

Monastic life declined greatly in the 15th century and Pope Clement VIII suppressed it completely in 1593 when it was no longer supposed to maintain a community, the patrimony of Gualter and its revenues were added to those of the chapter of Solsona. From then on it was a simple parish church, and maintained this status until 1936. During the Civil War, the church was turned into a powder magazine and in 1939, during the Republican retreat, it was dynamited. The place is still in ruins, although in recent years consolidation and refurbishment work has been carried out on the remains, which still show the grandeur of the church that was consecrated in 1207. The cloister has also been restored and the adjoining rooms have been adapted as the headquarters of the Baronia de Rialb Town Hall.