Albertus Pictor's paintings on walls and vaults in about thirty churches in the provinces around Lake Mälaren constitute a medieval picture treasury that is unique for the whole of Northern Europe. Our knowledge about Albert changed radically during the 1990s. What was formerly thought to have been painted by his supposed teacher Peter has proved to be the youthful work of Albert himself. It is now time for broader and deeper research on the topic, with close cooperation between art history and linguistics. In the new state of research and with new digital photographic and computer technology, a number of questions are calling for answers, especially the previously unstudied questions about interaction with the commissioners of artworks in the Middle Ages, and about the relationship of the paintings to the liturgy and the congregation. The other main component of the project is a detailed investigation of the text ribbons on the painting which are in Latin, the language mostly used by Albert. This has not previously been subject to scholarly study, but for our times it is a key to the interpretation of the function of the paintings and is doubtless an important source of knowledge about Albertus Pictor and fifteenth-century society. The project will result in a doctoral dissertation in art history concerning the questions now raised, a catalogue raisonné of the pictures, and a scholarly linguistic edition of the texts on the pictures. The results of the project will thereby make the paintings much more accessible, not least for the general public.