Proper nouns ending in -e and -o do not fit the classical morphologic patterns for masculine substantives in Slavic. As these elements resemble Slavic vocative endings and as on the synchronic level there is evidence for a reinterpretation of vocative endings as diminutive and hypocoristic suffixes, the paper addresses the question of the origin of Slavic proper nouns in -e and -o considering the vocative a possible source. After reviewing the various theories produced by linguists and philologists on this topic, a new hypothesis is formulated. On the basis of the functional proximity and the similar formation strategies between vocative and proper nouns, vocative is claimed to have contributed to the stabilization of proper nouns in -e and -o in Slavic and, more generally, to represent a source for creating new anthroponyms
