The domus Alliata, belonging to the prestigious family from the Valdera which boasts noble descendants also in Sicily, is the result of the combination of eleven tower houses, built between the 11th and 14th centuries. At the beginning of the twelfth century, Pisa was facing a moment of great demographic growth and many families took advantage of it to build their homes along the river, the designated place for every trade. Thus many tower houses were born, withartisan shops and warehouses on the ground floor, private quays on the river and living quarters (apartments, or rooms) that overlapped creating a modular scheme. The presence of different styles in the domus Alliata, both on Lungarno Gambacorti and on Via Mazzini, gives us an idea of the complex creative inspiration of Pisan architects, characterised by the use of round or pointed arches, pillars in Verrucana stone or marble, brick arches and mighty lintels. Palazzo Alliata is a true compendium of medieval Pisan civil architecture.