The founding of new county towns ran parallel to the growth of existing urban centres, an expansion set in motion by the activation of trade and the emergence of a class of craftsmen. Cities like Barcelona, Vic, La Seu d'Urgell and Girona spread beyond their walls and formed new districts or new towns. Barcelona experienced greater growth than any other city. Religious buildings, the county curia and the Jewish quarter were gathered together within the walls, while the craftsmen and merchants established themselves outside. Manufacturing and the city's markets benefited from the busy maritime traffic.