The aim of this study is to examine, by analysing marital origin-related homogamy and mobility, the fluidity of a system of social stratification marked by a heterogeneous working class and likely to lead to increasing social-group solidarity during the phase of a more active labour movement in the early twentieth century. Data from Winterthur, a Swiss town characterized by the expansion of an important engineering industry, reveal that occupational homogamy was most pronounced at the top, among higher managers and professionals, and at the bottom of the social hierarchy, among unskilled factory workers. There is no empirical evidence of increased homogamous behaviour after the nationwide general strike of 1918, which is said to have had a long-term impact on workers' class-consciousness. Our analyses show, however, that the association between the social background of spouses depended on their geographical origin. This result may point to a regionally determined class-consciousness.