The building known as 'Terme di Mesumundu' or the Church of Santa Maria di Bubalis, located in Siligo, represents an exceptional example of historical and architectural stratification in Sardinia. This monument, which blends elements from different epochs, rises on pre-existing late-imperial Roman structures, specifically a thermal complex that exploited the waters of the nearby spring of S'Abba Uddi. This continuity of use of the site testifies to the strategic and cultural importance of the area through the centuries.
The transformation of the building into an ecclesiastical structure dates back to the Byzantine era, a crucial period in the history of Sardinia that left significant traces in the island's architecture. The dating to this period is supported by the use of a distinctive building technique known as opus listatum. This methodology, characterised by the rhythmic alternation of rows of red brick and basalt stones, not only gives the building a visually appealing appearance, but also represents tangible evidence of the Byzantine influence on Sardinian architecture.