Very common name in Estonia, which was under German rule and influences for centuries and so naturally the name derives originally from the German Reinhold/Reinhard, but is a longstanding name in and of itself in this form. Our Latvian neighbours to the south share the same historic influences; their form of the name is Reinis.

This name is also used in Frisian and in Dutch; in the latter, it's often short for names like Reinier and Reinout. [noted -ed]

This name is absolutely beautiful!