Gloucester's importance was its strategic position in relation to South Wales. The crossing of the Severn controlled by the town was  secured by a castle, which was rebuilt on a more substantial scale in the early 12th century. The proliferation of Gloucester's religious institutions and the attraction to it of a large Jewish community are among indications of the economic vitality of the town during the 12th and 13th centuries. Gloucester's trading connections with the smaller market towns of its region and its own local market area were among the diverse elements that provided its livelihood. It had an industrial base supplied in particular by ironworking, for which it was widely known at that period, and by clothmaking; it played a part in the trade of the river Severn and, mainly through Bristol, in overseas trade; and its control of the trade routes out of South Wales benefited it from before the time of the Edwardian conquest.