Palazzo di Fraternita was built in the second half of the 14th century (but only completed a century later) by the Fraternita dei Laici, an ancient Aretine charitable institution, which made it the seat of its highest Magistrato.
Spinello Aretino, Bernardo Rossellino and Giorgio Vasari were involved in its construction at various times. At the end of the 18th century, it became the seat of the Ruota Civile (Civil Court), and it is still used for the same purpose, in that it houses the offices of the Tribunale (law-court).
In the lunette in the facade, above the valuable portal, there is Spinello's detached fresco of "Christ between Madonna and S.Giovanni" (1395), surrounded by statues by Rossellino and a basrelief of the "Madonna of Mercy". The bell-gable, built half way through the sixteenth century together with the coping, houses one of the oldest working clocks (the work of Felice da Fossato, 1552), which indicates hours, days and the phases of the moon.