Other than the castle, the principal engine of growth for the town was its regular market, for which the earliest known reference is in 1223. Many of the early buildings were grouped around the market area. These houses were built of highly perishable materials, and none have survived. Most would have been about a perch wide (about 5 metres), with long gardens at the rear, opening onto back lanes. On market days country people would bring their produce to sell at stalls in the open air. Apart from foodstuffs, the principal trades were in wool, cloth and leather, and related trades such as weaving, whitening, quilt-making and cobbling. These were largely determined by the predominance of shepherding in the surrounding agricultural area.