Rastsislau

Rastsislau is the Belarusian form of a Slavic name built from two old roots: rasti, to grow, and slava, glory. Put together they give the meaning recorded here, growing glory. The Polish cousin is Rościsław, and both belong to the wide family of Slavic compounds that close on the element -sław.

The oldest bearers were princes. Rastsislau of Moravia, a ninth-century ruler, asked Constantinople for teachers who could preach in a Slavic tongue, and the mission of Cyril and Methodius followed from that request. His name stated its own hope plainly: one whose glory grows.

In a school class register the name reads long and formal, and a teacher reaching it slows on the middle syllables. It shortens easily in speech. What stays is the meaning close under the surface, wzrastająca sława, the same two roots that Rościsław carries in Poland next door.