The square is set between the narrow S.Marta St and Morigi St, on the Roman Mediolanum. In this area, Roman walls were found and then covered again. Moreover, Santa Marta monastery, one of the richest of the center, was here. It was founded by Augustinian nuns in 1345 and then closed in 1799.
At the center of the square there is the Mentana’s battle war memorial, made by Luigi Belli, a sculptor coming from the Piedmont Region. The Battle of Mentana was fought on November 3, 1867, near the village of Mentana, in the Lazio Region, between French-Papal troops and the Italian volunteers led by Giuseppe Garibaldi who were attempting to reach Tivoli and capture Rome, then the main center of the peninsula still outside of the newly unified Kingdom of Italy. The war memorial was inaugurated in 1880, with the participation of Garibaldi who at the time was very old (he died in Caprera in 1882).
Nowadays, Mentana Square is the most important area of 5Vie district: its name comes from the Battle of Mentana, but the square is now the center of another battle between cultural and historical heritage and wild parking.
In 2017, after a massive awareness campaign conducted in the area by the association 5Vie, it was awarded as Luogo del cuore Fai.