This medieval surname is recorded in over fifty different spellings, and is one of the most famous. It derives from the Latin "castrum", a camp, through the 9th century castel, to the later castillo, chatel and chateau, and describes a person who lived in a castle or chateau. It is recorded in every European country, but has particularly aristocratic associations with Spain, Portugal and France, where nameholders held claims to be known as the Kings of Lyon. The basic spellings frms include Chateau, Chatel, Cattel, Cathel (France), Castro and Castillo (Spain and Portugal), Castle, Kestell, and Cassell (England), Castello (Italy), and many others. To these have to be added the wide variety of patronymic and diminutive forms, which include Castelot, Castelin, Cattelin, and rarer forms such as Cathelin and Cattellion. These later names are over-lap spellings, which may derive from the original "chatel" or may equally be forms of the female given name "Cateline", first recorded in the 12th century. This originates from the Greek "katharos" meaning pure and clean, and was a name introduced by the Crusaders, on their return from the Holy Land.The first recorded spelling of the surname in the church registers is possibly that of Andreas Medina de Castro, which was dated December 13th 1556, at Nuestra Senora de la Antigua, Valladolid, Spain, during the reign of King Charles 1st of Spain, 1519 - 1556. 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.