Known for its double moat and extensive Italian-style garden, the castle in Gaglianico seems to have been built in two distinct phases. During the first phase, characterized by a more defensive construction, the internal Tower would have been built, today edged by an angular keep. During the second phase, desired by Sebastiano Ferrero, which probably took place around the 15th century and is the work of Carlo d’Ambroise, the courtyard and four angular towers were added to those already existing. The castle, with a quadrilateral layout, is one of the best preserved structures in the Biella area.