The dense urban networks that developed in the period of medieval growth in the core principalities of the Low Countries were characterised in particular by a multitude of medium-sized and some larger cities. The network quickly outgrew its regional dimension both in terms of dependence upon supply from its agricultural hinterlands and as a reservoir for labour, and became intrinsically linked to an international economy for its outlets for industrial products, most notably woollen textiles in the southern Low Countries. Neither the density nor the scale of the urban system can be explained without taking into account the export-oriented industrial developments. Hence a hierarchical and integrated urban system came of age headed by an international commercial gateway: Bruges in the fourteenth and fifteenth centuries and Antwerp in the sixteenth. From the late Middle Ages onwards, difficulties arose in the cloth industry. While industrial relocations of textile manufacture occurred in favour of smaller towns and of the countryside, the cities in the south started to focus on the manufacture of durable consumer goods, fashion and luxury products. In the north, most notably in Holland, specialisation in transport, fisheries and trade paved the way for the Dutch Golden Age.