Рабан Мавр
Other monothematic names originate as surnames (bynames) rather than hypocorisms of old dithematic names; e.g. Old English Æsc "ash tree", Carl "free man" (Charles), Hengest "stallion", Raban "raven" (Rabanus Maurus), Hagano/Hagen "enclosure", Earnest "vigorous, resolute".