This interesting surname is of Anglo-Saxon origin, and is a habitational name from Mortlake in Surrey, derived from the Olde English pre 7th Century byname "Morta", of uncertain etymology, but it may be from the fish-name "mort", meaning "young salmon", originally given as a nickname, and the Olde English "lag", marshy meadow, or "lacu", a stream; hence "stream frequented by young salmon". The placename was first recorded as "Mortelaga" and "Mortelage" in the Domesday Book of 1086, and as "Mortelak" in the Close Rolls of 1228. The surname development since 1273 (see below) includes the following: John Mortlake (London, 1565), and John Morelacke (London, 1581). Recorded in the English Church Registers are the marriages of Ambroseius Mortlock and Margareta Thurnall on January 18th 1635, at Burwell, Cambridgeshire, and of Richard Mortlock and Hannah Gotto on October 13th 1783, at St. Saviour's, Southwark, Surrey. A Coat of Arms granted to a Mortlock family in Cambridgeshire is red, a lion rampant gold, a border indented of the last, the Crest being a lion segreant gold, resting the dexter paw on a cross pattee fitchee azure. The Motto "Hic labor hoc opus", translates as, "This is the difficulty, this the task". The first recorded spelling of the family name is shown to be that of Walter Mortlake, which was dated 1273, in the "Hundred Rolls of Cambridgeshire", during the reign of King Edward 1, known as "The Hammer of the Scots", 1272 - 1307. 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.