THE CLOTH INDUSTRY IN MEDIEVAL WALES THREE-QUARTERS of a century ago, in 1903, Edward Lewis addressed the Royal Historical Society in London on the subject of industry and commerce in medieval Wales. Prominent in his treatment of the cloth industry was his use of the evidence of fulling-mills. This remarkable article has been quarried, off and on, by Welsh historians and William Rees built splendidly on some of it; 2 but it has had no real successor and its pioneering use of evidence did not affect study of the English cloth industry until in 1941 Professor Carus-Wilson started afresh and redirected thinking about the development of cloth manufacturing in medieval England. 3 In what she described as 'an industrial revolution of the thirteenth century', Miss Carus-Wilson focussed attention not on the evidences of trade in wool and cloth, but on the introduction of mechanised fulling as an indicator of the geographical and chrono- logical spread of cloth-making on a commercial scale. Although the conclusions reached in that wartime article of 1941 cannot now stand without modification, part of Miss Carus-Wilson's basic methodological approach-which was also Lewis's-remains valid today. The fulling-mill is important as a determinant of industrial development simply because it is the only widely available index of capital investment in the textile industry during the later middle ages. Most woollen cloth was fulled after weaving. Fulling served the dual purpose of cleaning the cloth and consolidating the texture, by beating the cloth in a cleansing solution and finally washing the solvent away with a liberal supply of fresh clean water. This beating might be done by treading the cloth in a tub with the feet, as in Roman times, or, as was increasingly common 1 E. A. Lewis, 'The Development of Industry and Commerce in Wales during the Middle Ages', Transactions of Royal Historical Society, new series, XVII (1903), 121 75. Cf. idem, 'A Contribution to the Commercial History of Mediaeval Wales', Y Cymmrodor, XXIV (1913), 86-188. 2 W. Rees, South Wales and the March, 1284-1415: a Social and Agrarian Study (London, 1924); An Historical Atlas of Wales from Early to Modern Times (London, 1951); Industry before the Industrial Revolution (2 vols., Cardiff, 1968). E. M. Carus-Wilson, 'An Industrial Revolution of the Thirteenth Century', Economic History Review, orig. series, XI (1941), 39-60; reprinted in her Medieval Merchant Venturers: Collected Studies (London, 1954), pp. 183-210. References hereafter are given to the original article with the corresponding pages in the Collected Studies shown in brackets.