This historic centre of the city is home to the cathedral and the 12th-century Château-Vieux (so named in comparison to the Château Neuf built in the 13th century in Petit Bayonne). Traditionally a market town, this is where the shops and chocolate makers are based. Hemmed in by ramparts, the town had no choice but to grow upwards. The timber-framed buildings, whose width is strictly regulated (5 m maximum), were built between the 17th and 19th centuries.