This is almost certainly an English surname, although there are known to be at least three possible origins, and there may be a French element. The surname has many spellings as shown below, greatly adding to the confusion. The first origin is from the Roman (Latin) clan name Silvanus, a personal name meaning the God of the Forest and probably found in the spelling as Salvin. The second is from the French word and later surname Salvagin meaning as it (almost) says, a wild or savage person. It is said to have been introduced into the British Isles by the Norman conquerors at 1066, and given the robust humour of those times a thousand years ago, may well mean the reverse!. The third possible origin is from the Olde English personal name Selewine, occasionally found in the modern spelling of Selwyn. This translates Sea-friend. The surname development over the centuries has included Seluuinus de Warwick in the famous Domesday Book of 1086, Paganas Selewin of Bedford in 1203, and Sir Gerald Salevyn of York in 1320. The modern surname spellings include, Sauvain, Sauven, Savin, Savine, Salvin, Selwin, Selwyn, and Sylvaine. The first recorded spelling of the family name is shown to be that of Robertus Selivein. This was was dated 1195, in the Fines Court of Norfolk during the reign of King Richard 1st, known as "The Lionheart", 1189 -1199 Surnames became necessary when governments introduced personal taxation. In England this was sometimes known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.