This unusual name is of medieval Portuguese origin, and is a variant form of the more common Portuguese surname Castel-Branco or Castelo-Branco. The surname is locational in origin, deriving from a place called Castel-Branco; the place is named with the Portuguese elements "castelo", castle, from the Latin "castellum", a diminutive of "castrum", fort, with "branco", white. In some instances, the surname may also have been topographical, from residence near such a "white castle". The recordings of this name are very sparse, probably due to the destruction of archives in times of war, and those available are late and restricted to South America, where the surname was brought by Portuguese settlers during the 17th and 18th Centuries; the countries of Brazil and Colombia offer the only examples. In the latter country, the christening of Marcelino, son of Agustin Castiblanco, was recorded on May 30th 1865, in Guacheta, Cundinamarca, and in 1878, the christening of Marcelino's son, Adan, was recorded in the same place. The first recorded spelling of the family name is shown to be that of Jorge de Abreu Castelo-Branco, which was dated 1749, a christening witness in Sao Paulo, Brazil, during the reign of King John V of Portugal, 1706 - 1750. 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.