The castle of Pagazzano is a castle located in the homonymous locality. The current structure dates back to the beginning of the fourteenth century, when it was built in place of a previous defensive construction that was supposed to rise near the church dedicated to Saints Nazario and Celso. It was in fact customary that the early medieval fortifications of the Bergamo plain were built next to sacred buildings, then at the center of popular life. And, like most of the castles of that period, it was abandoned and repositioned not far from the end of the thirteenth and the beginning of the fourteenth century in the first free building area on the edge of the town. The need for a defensive castle was due to the strong political instability in the medieval age of the village of Pagazzano and the whole central Bergamo plain: first assigned to the counts of Bergamo in the eleventh century, it passed to Milan after the peace of Constance, together with the other castles of the Gera d'Adda. The dominion in the Milanese city was first practiced by the Torriani and, after numerous struggles, by the Visconti. It was the latter who built the new castle during the regency of John, at the death of which (1354) took over Bernabò. At that time dates a plaque that, placed inside the manor, recalls a reception in honor of Filippo Borromeo occurred in the year 1355. Tradition also wants that in the rooms of the building dwelt for some time the poet Francesco Petrarca who intercedes near Bernabò in order to preserve and improve the structure of the castle itself. During the fifteenth century Gian Galeazzo Visconti gave the castle first to Bertolino Zamboni of Cremona, then to the Suardi family. The subsequent settlement of Filippo Maria Visconti brought the castle back to the Cremonese family of the Zamboni, who retained possession of it until 1428, the year in which the territories were acquired by the Republic of Venice. A period of great instability began, with the area disputed by Milan and Venice: in those years the manor was entrusted first to Sagramoro, belonging to the branch of Brignano dei Visconti, and then to Francesco de'Isacchi di Treviglio. In 1447, with the establishment in Milan of the Ambrosian Republic, the Gera d'Adda passed again to the Serenissima, and the castle of Pagazzano was again assigned to the Brignanese branch of the Visconti family. This family maintained control of the building even when, with the construction of the Bergamo ditch and the definitive stabilization of the boundaries, Pagazzano returned under the influence of Milan. The stability, sanctioned by a notarial deed that, dated 1465, confirmed the full possession of the building at Sagramoro II Visconti, brought the castle to a series of modernization interventions: both the moat and the perimeter of the enclosure were extended, the external part of which it was covered in brick, to which four towers were added at the corners. In 1551 the castle of Pagazzano passed to Galeazzo Visconti, archpriest of the village, who made a series of changes that brought him closer to a stately home: on the south side the two towers were destroyed and the whole battlements were destroyed, while the north side was left intact in its defensive functions. The castle has a plan with a square section surrounded by a defensive moat still today watered down, the only example in the whole of Bergamo. The walls, perfectly preserved, has an external brick curtain and two towers, at the corners of the side facing north, which have archers and circular holes. The keep also stands out, which has long and narrow brackets and a gate and a winch, to protect the entrance, which was accessed via a main drawbridge and a pedestrian one. In this regard it is possible to find sixteenth-century frescoes that emerge under seventeenth-century squares, as well as numerous additions, including the loggia and the stairway.