This interesting name is Gaelic in origin, and is the Anglicized form of two Gaelic personal named that, over time, have coalesced into one, usually written as "Muire(adh)ach". The two original names were "Muiredach", a derivative of "muir", sea, which meant "belonging to the sea", a mariner and "Murchad", meaning "sea-warrior". The resulting personal name was introduced into Yorkshire before the Norman Conquest of 1066 by Norwegians from Ireland, and is recorded in the Domesday Book of 1086 as "Murdac, Murdoc" and "Meurdoch". The modern surname is thought of as Scottish, but it was not until the reign of William the Lion, King of Scotland (1165 - 1214) that one Walter Murdoch is recorded as witness to several charters. William Murdoch (1754 - 1839), the inventor of gas-lighting, was proclaimed a deity by the Shah of Persia, who believed him to be a re-incarnation of Merodach or Marduk, "God of Light". The first recorded spelling of the family name is shown to be that of Geoffrey Murdac, which was dated 1130, in the "Pipe Rolls of Yorkshire", during the reign of King Henry 1, known as "The Lion of Justice", 1100 - 1135. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.