Recorded in a wide range of spellings including Masden, Masdin, Masding, Masdon, and the more esoteric forms of Masedon and Massedon, this is an English surname. It is clearly locational, but as to which place it originates from, is far from clear. There does not appear to be any known place of the same spelling in any of the gazetters of the British Isles for the past three centuries. This strongly suggests that it derives from a now "lost" medieval village, of which the only surviving public memory in the late 20th centurey, is the surname itself. An alternative suggestion is that it is a form of something else such as the name Marsden, from villages in the Colne Valley in West Yorkshire, or the similar named villages in the adjoining county of Lancashire. In both cases the meaning of the name is probably either the boundary marker in the valley, from the pre 7th century Olde English "mercels-denu", or "mersc-denu" meaning marshy valley. The further a surname travelled from its original home, the more likely it was to develop "sounds like" spellings. In this case the surname is well recorded in the diocese of Greater London. Examples of the recordings include: John Masden, a witness at St Margarets, Westminster, on August 13th 1619, Bridget Masedon, who married John Leech at St Katherines by the Tower (of London) on October 23rd 1643, and Thomas Masding, who married Ann Dunn at the famous church of St Mary-le-Bone, on September 26th 1808.