This very interesting and unusual name is of Anglo-Saxon origin, and is from a nickname surname for a clever or cunning person. The derivation is from the Olde English pre 7th Century "gcap", which meant originally "open" or "wide", although it also had a later meaning of "curved" or "bent". However, it is thought that the latter meaning did not influence the surname formation. A sizeable group of early European surnames were gradually created from the habitual use of nicknames. These were given in the first instance with reference to occupation, or to a variety of characteristics, such as physical attributes or peculiarities, mental and moral characteristics (as in this instance), supposed resemblance to an animal's or bird's appearance or disposition, or to habits of dress. This name is particularly prevalent in the West Midlands. Recordings from London Church Registers include: the marriage of Margarett Yapp and Robert Busby on February 2nd 1622, at St. Botolph's, Bishopsgate, and the christening of Anne, daughter of Richard and Christina Yapp, on December 8th 1665, at St. Dunstan's, Stepney. The first recorded spelling of the family name is shown to be that of Richard Yap, which was dated 1200, in the "Pipe Rolls of Nottinghamshire", during the reign of King John, known as "Lackland", 1199 - 1216. 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.