This ancient name is of pure French medieval origin although the meaning is much the same as in English or German. The derivation is from 'cild' meaning 'a child' but generally a specific of the eldest son, although Robert Child, C. 1202 of Norfolk, was apparently the youngest son! The Normans also used the term as a status most equivalent to a sergeant at arms. By the Age of Chivalry (c. 1415), it was a term applied to a young noble. This was clearly the case with Chilley, who were of noble rank and held as such, their coat of arms being a gold field charged with the red sword belt of command. The first recorded spelling of the family name is shown to be that of Guillaume Chilley which was dated C. 1680 Besancon, France during the reign of King Louis X1V The Sun King 1643 - 1715. 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.