The Musée du Biterrois occupies a former military barracks adjacent to the cathedral, and covers the history and natural history of the Béziers region from prehistoric times to the 20th century. The strongest sections deal with Roman Béziers — Baeterrae was a significant colony on the Via Domitia, and the excavated material is substantial — and with the construction of the Canal du Midi, which has a dedicated room with original technical drawings and models.
The natural history collections, which include local geology and fauna, are less compelling than the archaeology but provide context for the garrigues and wetland landscapes of the surrounding Languedoc. The museum is rarely crowded and makes a useful hour before or after the cathedral. Entry is inexpensive and the building itself, an 18th-century barracks with a fine central courtyard, is worth a look.