The main objective of the project “Late medieval notions and ideas of work” (LABOR OPUS ARS) is to examine historical ideas and concepts of work in the late medieval period and origins of work ethics. The research will concern the 13th-15th century sources, and will make part of social history. However, as it will base in a great extent on analysis of scholastic texts, so it will be related to history of philosophy. The project will continue the previous research of the applicant in the framework of the Marie Curie project, concerning origins of management and enterprise ethics. The research will be focused on examining: a) development of the notion of work and its meaning in the medieval language; b) interconnection between the historical evolution of views on labour and the economic and social changes (taking into consideration long time economic cycles); c) inter-civilisation differences in ideas of labour, especially between Medieval-Latin, Byzantine, and Arabic civilisation; d) influence of ethical appreciation of work on the analytic concept of labour as the source of value and wealth. The research will also include scrutiny in collection of manuscripts and ancient book, with particular emphasis on Central European libraries resources (Cracow, Erfurt, Kórnik, Lublin, Olomouc, Pelplin, Prague, and Wien). The name of the project refers to Latin terms: labor; opus which signifies not only certain output of labour, but was also refers to notion of economic value (opus-indigentia); and ars considered largely as a specialised activity. The project presents first of all historical interest, but also searches into foundations of contemporary concepts of work and work ethics, referring to influence of the idea of work on the economic mentality of society in different civilisations, too.