Grünstadt – or rather the southern settlement around Saint Martin's – had its first documentary mention on 21 November 875, when King Louis the German restored this estate to the Glandern Monastery near Metz. The place was already called "Grinstat" in this document, and the ownership rights already went back further, as they were only being restored. This settlement, therefore, was considerably older than that 875 document, which had nothing to say about the estate's buildings. It is assumed to have been a monastery estate with a small church, out of which grew first a Benedictine priory which was newly built several times, and then today's Protestant Saint Martin's Church, with the burial place of the House of Leiningen-Westerburg.