Piazza Mastai in Rome gets its name from the family of Pope Pius IX, who constructed the Manifattura dei Tabacchi there in 1865.
Piazza Mastai Rome
The building still exists, although the Pope himself was not too enthusiastic about the result. According to legend, after Pius had entered the building through the door, which was rather small compared to the rest of the building, he is supposed to have said: “Now I have entered through the window, I would also like to see where the door is”. It is safe to say that this was probably a lot wittier in Italian.
Except for the Manifattura dei Tabacchi, Pius IX also constructed a number of rental houses for those Trasteverini who did not have a sufficient income. The houses still exist, in the Via Cardinale Merry del Val, which used to be part of the Piazza Mastai.
The central fountain in the square, like the Manifattura, was designed by the architect Antonio Sarti.