Between the 10th and 14th centuries Pisa had its most important period of expansion, thanks to trade and military power. The noble families began to show their wealth especially through construction, with houses that stood out in height: the tower houses. The particular shape of thepointed arches, built perhaps with the use of the frames obtained from the ribs of the galleys (which create the skeleton of the ship), allowed to unload the weight of the pillars in Verrucana stone, sandstone or even marble. The shelves that protrude from the walls were used to support a system of woodenbalconies and bridges, useful as a connection with other towers, or simply to increase the floor area. The first windows were small, but over the centuries they became larger and more elegant, with marble columns and lobes and decorated ferrules. The Case Miniati complex is composed of four tower houses built between the 12th and 13th centuries. From Via A. Volta there are: Casa Miniati, two pre-existing towers with a structure in white and Verrucan limestone, typical of the royal lines, present in the most representative buildings (where we often find two-tone bands, as in the religious buildings of the Piazza del Duomo); Casa Prini, with a single arch; Casa Golfieri, with a double arch with mullioned windows in Verrucana stone. The tower houses had a shop or a stable on the ground floor, going up there were the overlapping living quarters and on the top floor, often in wood, the sentry box for the soldiers or the kitchen/pantry room.