The male name Stas in Ukraine has been recorded since the mid-16th century. For example, in 1542, a Stato Oros is mentioned in the village of Luh (Belay 133); in 1620, Stas Velikiy is noted in the village of Hubyn (VKO 464). Near the city of Peremyshl, the name Stas has been known since the 15th century (Rieger mapa 4), and it is also present among the Poles (SSNO V 197). Additionally, in 1649, a Cossack from the Kyiv regiment named Stas Pavlovych is known (RVZ 308), along with Cossacks from the Bratslav regiment named Stas Voitenko and Stas Kramar (RVZ 245, 253). In Belarus, the name Stas was used throughout the 15th to 17th centuries, although Stas was often recorded as a variation of Stanislav (Bir 156).The researcher of Ukrainian names of the 16th century, R. Y. Kersta, does not even attempt to differentiate personal names such as Stasko, Stan, Stasz, Stachno, Stasieczko based on their etymological origins (Kersta, XVI ст. 14). Genetically, the name Stas is a Slavic suffix formation that arose from the calendar name of Greek origin, Eustachius (through stages of variations such as Ostap, Stakh). The functional merging (or even identification) of the name Stas with the homonymous name Stanislav occurred only over time; the primary motivation for their differentiation was the phonetic similarity of their initial parts.
