The history of the welfare state is usually told from a national or nationally comparative perspective as it still counts to the «bastion of the nation state» (Conrad). This perspective neglects that influential international discourses on social policies already emerged during the 1850s and in fact preceded as well as accompanied the constitution and development of social insurance systems – the core institution of the modern welfare state – which only began in the 1880s. Although public as well private actors carried on these debates throughout the 20th century, only recently historical research has started to examine the significance of international organizations and transnational transfers for the development of the welfare state. From this perspective, the project deals with two of the leading associations of insurance experts, in particular of insurance mathematicians and statisticians, the International Congress of Actuaries (ICA) and the International Social Security Association (ISSA), focusing on the second half of the 20th century.