A baptismal name for a boy
Rastislav
One saint bore this name
Saints named Rastislav
Questions
The name day of Rastislav is May 11, the feast of Right-Believing Rastislav of Moravia.
The Sinaxarion archive holds 1 saints named Rastislav, with their lives and icons.
Yes. Rastislav is the name of a saint of the Orthodox Church, so the child will have Right-Believing Rastislav of Moravia as patron.