The history of the definite adjective in Baltic has been the object of a considerable tradition of research. Most studies approach the problem from an angle which emphasizes the prehistory of the construction and its deeper genealogical ties as well as structurally comparable constructions in neighboring languages.

The present paper, however, is primarily concerned with a thorough morphological description of these constructions in the Baltic languages exclusively, and the trajectory of historical developments within attested diachrony. It will be shown that Lithuanian, Latvian and Old Prussian are best addressed independently as they provide rather diverse challenges to an adequate morphological classification. Special prominence will be given to wordhood issues in Old Lithuanian.