This piazza has hosted the Municipal Building since 1874, after having been home to a church dedicated to the Most Holy Annunciation and a monastery of Mercedari monks who arrived in Villacidro around 1650 and remained there until 1858.

In 1862, the local Council purchased the monastery and converted it in part into the Municipal Building and in part into a school complex. Burial grounds dating back to the Imperial Roman era were uncovered in the piazza during the excavation phase of its construction, bringing to light many sarcophagi and their relative grave goods.

This discovery illustrated the fact that these areas were populated in the past even more clearly: evidently, Villacidro’s old town centre was already home to a settlement of remarkable importance even during the Roman era. Currently, the building maintains some traces of its ancient origin like its inner courtyard. Town Hall offices and several elementary school classrooms overlook the courtyard. There is no trace left of the church dedicated to the Most Holy Annunciation, torn down in the 1930’s, except for those found in old photographs and in the memories of the town’s oldest citizens.