This interesting name is from a diminutive form of the personal name Giles, Julian or William. There has been considerable confusion between the variants of both personal and sur-names generated from these original names over the centuries, and it is no longer possible to assign separate derivations for the modern surname, which can be found as "Gill(i)att", "Gillyatt", "Gillot(t)", "Gillyett", "Gilyot(t)", "Jillett" and "Jellett", among others. The name Giles is derived from the Greek "aigidion", meaning kid, and was introduced into England by the Normans after the Conquest of 1066 as "Gille", with the diminutive forms "Gillet" and "Gillot", as in Gilot de Lackenby (1250, Yorkshire). Julian, and the female form Gillian, are derived from the Latin "Julins", from "Iuppiter", the supreme god, whose name is akin to words meaning "sky, light, day"; these have the diminutives "Giliot" and "Gilliatt". William derives from the French (Norman) "Guillaume", from the Germanic "wil", meaning desire, conviction and "helm", helmet, protection, giving the diminutive "Guillot" as in Guylote Belebonche (1319, London). Jenne, daughter of Oliver and Marie Gillet was christened at the French Huguenot Church at Threadneedle Street, in London on November 30th 1606. The first recorded spelling of the family name is shown to be that of Peter Gyllot (witness), which was dated 1260, in the "Assize Rolls of Yorkshire", during the reign of King Henry 111, known as "The Frenchman", 1216 - 1272. 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.