Another two remarkable buildings in the square are the Baroque Palatine School (Palazzo delle Scuole Palatine) and the Gothic House of Panigarola Family (Casa dei Panigarola).
These two buildings are one next to the each other in a corner of the square, as an extraordinary contrast of styles.
Built of black and white marble, the beautfiul Loggia degli Osii was commisioned by Matteo Visconti da Scoto of San Gimignano in 1316.
Although the building it was damaged during the years, the extensive restoration works carried out in 1904 tried to bring back its original form.
The building is housing today a branch of an Italian Bank.
This came as a total surprise for me during my visit to Milan. Although very close to Piazza del Duomo, I had no idea that this so-called "corner of old Milan" exists and is still preserved intact here.
It had six gates, one for each of the neighborhoods of the 13th century city, and in the centre stood the Palazzo della Ragione, or New Town Hall (Broletto Nuovo), commissioned by Oldrado da Tresseno, the first mayor of Milan.
Palazzo della Ragione or New Town Hall (Broletto Nuovo) is located on the south side of medieval Piazza Mercanti and is an austere building with has three rows of arcades supported by square pillars.
Piazza Mercanti is undoubtelly the most beautiful square in the city. The old Milan is still preserved intact here, although it is just a step away of traffic and ugly skyscrapers.
Originally square shaped, it had six gates, one for each of the neighborhoods of the 13th century city.
Do not miss to observe the magnificient buildings which stood around the square, such as Palazzo della Ragione, Loggia degli Osii, the Baroque Palatine School and the Gothic House of the Panigarola Family. Right in the middle of the square there is the 16th century well.