A Baroque palace built between 1608 and 1623, commissioned by Juan de Echávarri y Larráin, and belonging to a very influential family from Estella throughout the 16^th and 17^th centuries. Juan de Echávarri divided his time between the royal court of the House of Austria and his homeland: in Estella he acted as Justice and Governor, and in the royal court he was a member of His Majesty’s Council and treasurer to the Holy Crusade. As a result of his personal skills, he amassed a great fortune and reached a lofty social position. In 1609 he was granted the title of Baron of Purroy by King Philip III.

It is thought that the building’s plans were drafted by Juan Gómez de Mora thanks to the close relations between Juan de Echávarri and the Duke of Lerma, who Gómez de Mora worked for on numerous projects.

The building is noted for its horizontal aspect. The façade presents architectural features uncommon in this area, such as its combination of stone, in the framing of apertures, and brick, which connect it with palaces of the House of Austria style in Madrid. Three crests are the only decoration: in the middle we see the Arms of Juan de Echávarri; to the right, the Arms of his son; and to the left, those of his second wife.

The interior is arranged around an elegant square-plan patio and two floors with series of triple arches on Tuscan order columns of monolithic stone; each parapet on the upper floor is adorned with an oval-shaped crest set in a scroll frame containing the Arms of the Echávarri family: a star.

Since 2010, it has housed the Museum of Carlism.