Persian has a polyfunctional case marker, ‘rā’, which diachronically varies greatly in the range of functions it covers. In this paper, we give an account of different case functions of ‘rā’, in New Persian, an era from the 8th century (C.E.) to present. To analyze the functionality of ‘rā’ in different texts, we selected 78 books from the New and Contemporary Persian eras and studied one thousand tokens of ‘rā’ from each century. The data show that ‘rā’ has been a polyfunctional case marker in New Persian, marking about 13 different case roles. Its main role was to mark direct objects, and gradually it has become its sole function in Contemporary Persian. However, during the time span, some of the ‘rā’-marked roles remained constant and some of them replaced ‘rā’ with other adpositions. We follow a historical semantic map approach as a typological grid to examine our data. The findings show that ‘rā’ has shifted from animate to inanimate concepts gradually. While in the 12th century about 750 out of 1000 (about 75%) roles marked with ‘rā’ were animate, it has decreased to about 400 out of 1000 (about 42%) in the 19th century and less than 30% in the 20th century. Our data show that ‘rā’ has not gone further to mark inanimate relations, and it has gone toward core case roles, specifically direct object.
