This interesting patronymic surname is English. recorded in many forms as shown below, it is of medieval origins, and derives from the personal names Jacque or Jack, alternative spellings of the personal name Johan or John. This was a Crusader name introduced into Europe mainly in the 11th and 12th centuries, and deriving from the ancient Hebrew Yochanan meaning "Jehovah has favoured me with a son". To this was added the English suffix of -cock, which had the baptismal meaning of 'son of'. The surname from this source is first recorded in the early half of the 14th century (see below), and other examples include John Jecok in the court rolls of the borough of Colchester in the county of Essex in 1375, whilst John Jecokes, a double patronymic, appears in the assize court rolls of Warwickshire in 1381. A later example of the surname recording taken from surviving church registers of the city of London was the marriage of James Sharples and Elizabeth Jeacock at St. James Clerkenwell, in the year 1712. Modern spellings of the surname include Jeacock, Jeacocke, Jacox, Jecock, Jaycocks and Jaycox. The first recorded spelling of the family name is shown to be that of William Jacok. This was dated 1327, in the Subsidy Rolls of Suffolk, during the reign of King Edward 111rd of England, 1327 - 1377. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.