In this paper, the semantic roles expressed by the Dative case in Modern Russian and Old Church Slavonic are described in terms of radial categories. The corpus data shows that the radial category of the Dative case has changed since Old Church Slavonic. The radial category in Modern Russian is smaller, and it includes fewer subcategories than attested in Old Church Slavonic. The change of the category prototype could explain the changes in the category of the Dative case. Recipient is postulated to be the prototype of the Dative case category in Modern Russian, while Direction appeared to be the best prototype for Old Church Slavonic data.