Recorded in several spellings including Wattem, Wattam, Wattisham, Wattum, Watsam, Watsham and others, this is an English surname. It is locational either from a now 'lost' medieval village, or from the village of Wattisham in the county of Suffolk, or perhaps from any of the various places called Waltham as in Waltham in the county of Lincolnshire between Caistor and Cleethorpes. In all cases the place name and hence the surname mean much the same of "The settlement on the weald" from the Olde English pre 7th century 'wealh ham'. The intrusive 's' in the surname was dialectal and introduced to aid pronumciation, and a common feature of English surnames. The surname development includes such recordings as that of Jhon Wattum who married Elizabethe Wylsone at Killingholme, LIncolnshire on 30th April 1598, whilst some ten years later on July 26th 1608, Johes Wattam, was christened at the same church, and in the surviving registers of the city of London we have Robert Watsham, a christening witness at St Boltolphs without Aldgate, on January 21st 1749, and Elizabeth Wattisham or Wattinham who married James Smither, at All Saints, Wandsworth, on January 8th 1787. Surnames became necessary when governments introduced personal taxation. In England this was sometimes known as the Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.