This interesting name is of English locational origin from the parish of Kilsby in Northamptonshire six miles from Daventry. Recorded variously as Kyldesby circa 1050 in "the Anglo-Saxon Chronicle", as Chidesbi in the Domesday Book of 1086, and as Kildebi circa 1139, the place was so called from a Scandinavianized form of the old English pre 7th Century "cild", a young nobleman, plus the old Norse "by", a settlement. The surname is particularly well recorded in church registers of Northamptonshire and London from the late 16th Century. On March 6th 1596 Alex, daughter of Robart Kylsby, was christened in Long Buckby, and on March 30th 1617 Francis, daughter of Johannes Kilsby, was christened in Watford, Northamptonshire. John Kilsby, an infant, was christened in St. Dunstan's, Stepney, London, on October 28th 1658, and on April 13th 1663 Thomas Kilsby and Mary Henry were married in St. Mary Mountain, London. The first recorded spelling of the family name is shown to be that of Robart Kylsby, (marriage to Margery Marten), which was dated September 5th 1592, Long Buckby, Northamptonshire, during the reign of Queen Elizabeth 1, "Good Queen Bess", 1558 - 1603. 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.