[1] Built as a military fortress by Yblet de Challant in the fourteenth century, it was one of the first examples of a castle constructed as a single structure rather than as a series of buildings enclosed in a circuit wall.

Verrès castle thus became the centre of an inheritance dispute between Catherine who claimed it for herself under her father's will and some of her male cousins, including Jacques de Challant who contested the will on the basis of the Salic law, which did not permit succession in the female line.

In 1536, René renovated the fortress to take account of the appearance of firearms, with the help of the Spanish captain Pietro de Valle, a famous military architect.

He had the base of the cubic structure surrounded by a circuit wall with counterforts and polygonal turrets, adapted to cope with cannons and equipped with pieces of artillery brought from his fief of Valangin in Switzerland.

[15] The illustrious René de Challant, Count of Beaufremont, Virieu-le-Grand, Aymavilles and Coligny, Lord of the castles of Saint-Marcel, Issogne, Valangin, Montalto Dora, Graines, Verrès, Ussel etc., Lord Knight of the Order and Marshal of Savoy decorated inside this citadel built by the most excellent Ybalt de Challant and (fortif)ied the exterior with military structures.

[5] At Rene de Challant's death without male heirs in 1565, his property passed to his son-in-law Giovanni Federico Madruzzo who was married to his daughter Isabel, beginning a long legal conflict with other male members of the Challant family, once again based on the Salic law, under which Isabel could not inherit her father's property.

[5] The strong exterior walls held up well, but the wooden roof was removed as punishment for not paying taxes, leaving the top floor exposed to the elements.

[16] After a series of transfers[19] it was finally acquired from Alfredo d'Andrade in 1894 by the Italian state in 1894 and placed under the Superintendency for monuments of Piedmont and Liguria, which carried out restoration work.

[20] After the Second World War, the castle was declared a Monument of Italy and came under the authority of the Aosta Valley which rebuilt the stone casing in the 1980s.

[21] The castle, constructed as a military fortress, sits atop a rocky premonitory above the river Évançon and dominates the town of Verrès.

In addition to being difficult to reach and easy to defend, its position allowed it to control the country below: the central valley and the Val d'Ayas pass which was then an important route.

Et l'on peut dire sans exagération que c'est un des plus solides et plus fameux batiments qu'un vassal ait pu faire construire dans le domaine d'un prince souverain où celluy-cy tient le rang d'un des plus renommés And one can say without exaggeration that it is one of the most solid and most famous bastions that a vassal could have built in the domain of a sovereign prince – within which it is one of the most renowned.

Externally it is an austere cube, about 30 metres on each side, surrounded at the base by a circuit wall which encircles the entire summit of the peak.

The walls (some more than 2.5 metres thick)[5][22] are surmounted by a continuous line of battlements, which hide a storm drain, with Medieval mullioned and Renaissance cruciformed windows.

The visitor ascends on foot along a mule track, which winds up the mountain until it reaches the entrance in the circuit wall, accessed by means of a drawbridge.

This entrance, like the external circuit wall, was built by Rene de Challant in the sixteenth century, as indicated by the inscription above the gate.

[8][26][27] The inner courtyard of the castle is a simple square area from which two large halls, positioned on the east and west sides of the manor, can be accessed.

[31][32] The architrave of the first door which a person first meets as they climb the staircase bears the inscription which records that Yblet de Challant built the castle in 1390.

[8][26] The east side of this floor is taken up by the lord's bedrooms, heated by large stone fireplaces, covered by a cofferred wooden ceiling and equipped with a total of five latrines in the wall, which emptied onto the rocks below.

[36] In 1884, the manor was used by Alfredo d'Andrade as one of his models for the Medieval Castle and Rock in Turin, which was built for the Italian General Artistic and Industrial Exhibition of that year.

[37] Every year since 1949, on the occasion of the historic carnival, the people of Verrès celebrate the 31 May 1449, when Catherine de Challant and her husband Pierre d'Introd went down to the village square and began to dance with the townsmen.

For the four days of the carnival, the castle hosts dinners, Masquerade balls, and performance of Giuseppe Giacosa's play, Una Partita a Scacchi (A Game of Chess).