A eulogy in which Frantisek Vaclav Mares's (1922-1994) linguistic contributions are presented. Mares is recognized as one of the most prominent Czech linguists who advanced the state of linguistic research in the history of Slavic languages, Old Church Slavic in particular. Discussed are his publications on the diachronic phonology of Old Slavic, Old Church Slavic vocabulary & lexicography, Glagolitic & Cyrillic paleography, the Croatian & Russian versions of Church Slavic, & the place of Macedonian in the Slavic linguistic community. Mares's presence at various Slavic congresses & seminars where he stimulated new investigations, & his close collaboration with major journals on Slavic linguistics are mentioned. Z. Dubiel