 Osbourne and Hobbs' interpretation of Emsanternon suggests that it derives from the Welsh ynys for ‘water meadow’, nant – ‘valley’ which in turn evolved into meaning ‘stream [running through the valley]’, and the personal name Teyrnon, an early ruler of Gwent.No interpretation of Deuma is proposed but the further place name Vallium, mentioned in 1244, is derived from the Latin for ‘valley’.Further toponymical work on some of Llantarnam's granges has been carried out by Osbourne and Hobbs (1999