Maurice m. Latin Mauricius 'Moorish, Mauretanian'.
The name of a popular 2nd C Roman saint, a 6th C Byzantine emperor, and a 12th C French saint.
The vernacular English form Moris is witnessed in 1379 in the relational byname Morissoñ (WRYPT1 p. 292).
In Ireland, Maurice was used as an anglicization of Muircheartach.