ABSTRACT
This essay is divided into three parts: the introductory theoretical discussion will elaborate on the process of creating a work of art. Then one short case study of medieval wooden altarpieces and some aspects of their economic history will be presented. Finally, I would like to emphasise the role of the work of art as a primary historical source also in terms of economic history. The term 'barometer' in my title should of course be understood metaphorically. As will be shown, the reference is to the indexical function of the instrument: a visual sign of some occurrence outside the sign itself.
