You can't visit Castres without stopping by the Goya Museum, devoted to Spanish painters and the famous artist Francisco de Goya.
The museum is based in the former Bishop's Palace, a 17th-century gem with architecture by Mansart, one of the architects of Versailles, and gardens by Le Nôtre.
Initially organised around works by Goya, over time the museum has received donations including many pieces by other great Spanish masters. It is therefore famous for representing all of Spain's artistic creativity, from Antiquity to the 20th century, including works by Velázquez, Zurbarán, Pacheco, Cano, Sorolla, Uranga, Picasso, Miró, etc., and is second only to the Louvre for its Hispanic art collections.
As well as the pictorial collection, there is also a collection of coins from the 3rd century B.C. to the early 19th century, a remarkable exhibition of sculptures, and a collection of 400 weapons.