A charming corner in the heart of the Rione Trastevere, Piazza dei Mercanti has been a place of great importance over the centuries, thanks to its proximity to the ancient port of Ripa Grande.
In the square, in fact, took place the trade of goods transported by boats coming from the sea, which landed at the port, and by small vessels pulled by oxen along the riverbank.

Following the construction of the Apostolic Hospice of St. Michael at the end of the 17th century, the appearance of the square underwent significant changes, and many small buildings were incorporated into the new welfare structure; later, at the end of the 19th century, the port of Ripa Grande was eliminated to allow the construction of the embankments on the Tiber.

However, the square still retains the atmosphere of Rome in the past: at the corner with Piazza di Santa Cecilia, you can admire a charming tower-house, dating back to the second half of the 13th century, which was probably once owned by the Ordine degli Umiliati, a confraternity dedicated to the art of wool, suppressed by Pius V in 1571.
According to tradition, the building, known as the house of Ettore Fieramosca, hosted the famous Capuan leader on his return from the Challenge of Barletta in 1503. Now privately owned, the structure appears to be the result of a fusion of several buildings and is a rare example of a well-preserved medieval house. 
At the entrance, columns crowned by Ionic capitals and connected by brick arches indicate the existence of an original small portico, later walled up, reinforced by a lateral buttress. At the top of the body in the corner, the tufa wall shows a decoration of blind pointed arches on marble corbels, which may have delimited a loggia.
Nearby, it is worth mentioning the Museum of Santa Maria in Cappella, set up around the small church consecrated in 1090 and now housed in the Complesso di Santa Francesca Romana, a 19th-century hospital built by Busiri Vici, the Complesso Monumentale di San Michele a Ripa Grande and the Basilica di Santa Cecilia.
Piazza dei Mercanti has also been the setting for some important films of Italian cinema, such as Ladri di biciclette by Vittorio De SIca, Peccato che sia una canaglia by Alessandro Blasetti and Mamma Roma by Pier Paolo Pasolini.