The long association with wool meant that Haslingden and the other Rossendale towns had expertise with the processes of cloth production, and so were able to switch easily to cotton weaving. Cotton was better suited than wool to industrialised spinning as its fibres were less likely to break than wool. Cotton cloth manufacture quickly became a highly successful industry, and its development was closely associated with its role in the expansion of the slave trade. African slaves being bartered for cotton goods, and cotton being picked by slaves in the Deep South of the U.S. The growth of mills also had an enormous impact on the landscape, and on the lives of its work force. Cotton weaving in the new factories was largely unregulated, and the workforce kept almost at starvation levels. Hunger drove men and women to fight back, and mobs attacked the power-looms that were seen to be the cause of the decline in status of the workforce. In 1826 almost 3,000 people were reported as 'attacking machinery' in Haslingden. A troop of cavalry was stationed in the vicinity, and ring-leaders were arrested. It was reported from Haslingden in the same year, 1826, that 'a great majority of the unemployed must literally perish from extreme want'. By the 1850 steam power began to supersede water power, and mills grew in size. Grudgingly a minimum wage was introduced, and through the efforts of reformers, the churches and a few enlightened mill-owners, conditions for factory workers slowly improved. Conditions were still harsh, despite the whole Rossendale area being known as the 'Golden Valley'. No longer dependent on the rivers as a source of energy, the mill owners were freed to build elsewhere, and Haslingden began to find that successful mills, such as Hargreaves Street Mill, could be built on its higher land.