This square with its odd elongated shape is part of the axis of large roads to the north of the medieval city built after 1550. Initially an area of lower-class houses and brothels, this square, closed in among the frescoed and decorated façades of patrician mansions, was later used by the aristocracy for their tournaments. The most prominent buildings around this square are 15th-century Palazzo Spinola dei Marmi (at number 6), decorated with black and white stripes and statues of five family members; Palazzo Ayrolo Negrone (at no. 4), with its imposing 18th-century façade; and Palazzo Interiano Pallavini (at no. 2) dating back to 1565, with its delicately coloured frescoes. The origin of the square’s name is uncertain, though there is mention of it in the 13th century as a fons marosus, Latin for stormy, gushing fountain, perhaps due to the violence of its streaming waters. In the 15th and 16th centuries, instead, there is talk of a fons morosus, Latin for illicit or capricious fountain, possibly hinting at the presence of a public brothel in the neighbourhood. Whatever the origin, we know for a fact that in 1206 there were fountains here, which were refurbished and embellished with the opening of the New Street (Strada Nuova, now Via Garibaldi) in 1558. A triple-arched fountain was knocked down in 1849 when Via Interiano was opened, though its huge, 17-metre cistern now lies buried beneath the road.