Labour history or labor history is a sub-discipline of social history which specialises on the history of the working classes and the labour movement. Labour historians may concern themselves with issues of gender, race, ethnicity, and other factors besides class but chiefly focus on urban or industrial societies which distinguishes it from rural history. The central concerns of labour historians include industrial relations and forms of labour protest (strikes, lock-outs), the rise of mass politics (especially the rise of socialism) and the social and cultural history of the industrial working classes. Labour history developed in tandem with the growth of a self-conscious working-class political movement in many Western countries in the latter half of the nineteenth century. Whilst early labour historians were drawn to protest movements such as Luddism and Chartism, the focus of labour history was often on institutions: chiefly the labour unions and political parties. Exponents of this institutional approach included Sidney and Beatrice Webb. The work of the Webbs, and other pioneers of the discipline, was marked by optimism about the capacity of the labour movement to effect fundamental social change and a tendency to see its development as a process of steady, inevitable and unstoppable progress. As two contemporary labour historians have noted, early work in the field was "designed to service and celebrate the Labour movement." In the 1950s to 1970s, labour history was redefined and expanded in focus by a number of historians, amongst whom the most prominent and influential figures were E. P. Thompson and Eric Hobsbawm. The motivation came from current left-wing politics in Britain and the United States and reached red-hot intensity. Kenneth O. Morgan, a more traditional liberal historian, explains the dynamic: the ferocity of argument owed more to current politics, the unions' winter of discontent [in 1979], and rise of a hard-left militant tendency within the world of academic history as well as within the Labour Party.