This very unusual name is a female medieval job descriptive word (Dayester) for a Cow-herd, Swine-herd or other forms of a keeper of livestock. A similar type of surname would be Baxter, this being the female form of Baker, although the male form of Dayester is Dayman. The name was foreshortened in 16th Century to Dayer. The name development includes Ales Dayer who married Baruaby Salter at Ash (Surrey) in 1572 and John Dayer of London who married Ellin Cavey at St. Katherines by the Tower in 1610. The first recorded spelling of the family name is shown to be that of Emma Le Dayster, which was dated 1278, The London City Pipe Roll, during the reign of King Edward I, 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.