By the time of the Republic c. 509 BC, the number of sailors and fishermen making a living from the river had increased, and many had taken up residence in Trastevere.

In order to have a stronghold on the right Bank and to control the Gianicolo hill, Transtiberim was partially included by Emperor Aurelian (270–275) inside the wall erected to defend the city against the Germanic tribes.

In the Middle Ages Trastevere had narrow, winding, irregular streets; moreover, because of the mignani (structures on the front of buildings) there was no space for carriages to pass.

Thanks to its partial isolation (it was "beyond the Tiber") and to the fact that its population had been multicultural since the ancient Roman period, the inhabitants of Trastevere, called Trasteverini, developed a culture of their own.

In the sixties and seventies, the American musicians/composers Frederic Rzewski and Richard Teitelbaum, of the group Musica Elettronica Viva, lived in Via della Luce.

Sergio Leone, the director of Spaghetti Westerns, grew up in Viale Glorioso (there is a marble plaque to his memory on the wall of the apartment building), and went to a Catholic private school in the neighborhood.

In addition to the river, which marks the eastern border of the borough, the area is delimited to the west and to the south by the Janiculum walls, and to the north by the Galleria Principe Amedeo di Savoia-Aosta tunnel.

Westward, it borders with Quartiere Gianicolense (Q. XII), whose boundary is marked by the Aurelian Walls, alongside Viale delle Mura Aurelie.