Lu Palatzu of Baldu is a square-plan tower placed in the south-eastern part of the pentagonal complex which developed around it (fig. 1). Its height reaches about 10 metres, but it is possible that in ancient times it was higher as, in addition to the three floors which may be inferred, it must have had a terrace, which ensured a good visibility of the surrounding area.

Fig. 1 - Plan of Lu Palatzu (survey and graphic reconstruction by A. M. Azara).

The lower level of the tower was characterised externally by a talus, while inside there is still a large boulder whose function has not been yet clarified; it has been hypothesised that the surrounding space was used as a warehouse for storing goods.

Fig. 2 - The Palace of Baldu, seen from the South-East (photo by Unicity S.p.A.).

The three floors must have been used as living and administrative quarters which would justify the technique and elegance of the masonry and the presence of a series of large windows, as well as an external staircase that provided access to the ground floor (fig. 3).

Fig. 3 - The Palace of Baldu, staircase (photo by Unicity S.p.A.).

It has been suggested that the tower was the residence, at least seasonally, of the Giudice or the Bishop of Civita, but perhaps, quite simply, the representative office of the curator of Balaiana. According to tradition, this structure is connected to the Visconti family of Pisa, particularly to Giudice Ubaldo, who lived during the thirteenth century: this dating is appropriate to this type of tower, often used in the private residences of Pisan families.