In this monograph a brief historical overview is given with results of research on the Mordvin definite conjugation. Primary purpose is to present various diachronic layers of synthetic verbal forms in the context of author's previous historical-phonetical studies. The argumentation is rooted in a historical point of view and is mainly based on empirical material. During field trips to the Mordvin Republic Keresztes was able to supplement the earlier collections with contemporary language material. The monograph contains a sampling of the Mordvin definite verbal paradigms as well as schematic maps presenting the dialect variants of the definite suffixes along with the main isoglosses in the Mordvin dialect area, from the perspective of definite conjugation.