The municipality owes its name to a spring that rises at the foot of Monte Cerreto, a hill covered in pine trees, and with whose water, according to tradition, St. Marinus baptized new followers of Christianity.

According to legend, Marinus sought refuge in a cave in the Rupe della Baldasserona, located in the area of present-day Acquaviva, at the beginning of the 4th century.

A bronze figure depicting Mercurius sitting on a stone was found in the La Serra district.

On 19 December 1243, Guido di Cerreto granted the Republic of San Marino many rights, i.e. the collecting of taxes.

At the foot of the hill, was the information with which the Saint baptized the first Christians of the Titano community, and hence the name of "Acquaviva".