This name is one of the patronymic forms of the male given name Thomas. It is of biblical origin and derives from the Aramaic byname meaning "The twin", and was borne by one of Christ's disciples. In Britain it was rarely recorded and then only as a priests name, until after the 12th century Crusades to the Holyland. Thereafter it became the fashion for knights returning from these expeditions, to give their children Hebrew names. Later these names became surnames during the medieval period. The intrusive "a" is dialectal, and an aid to pronunciation at a time when "modern" English was being created.. The surname can also be found recorded as Thomasson and Thomerson. Amongst the recordings of this name is one Ann Thomason daughter of Richard and Mary Thomason who was christened on April 28th 1729 at St. Dunstan's, Stepney, London, whilst an interesting namebearer was James Thomason Lieutenant Governor, registrar and judge in the Bengal civil service and secretary to the Indian Government in 1830. He was appointed governor of Madras on the day of his death. The first recorded spelling of the family name is shown to be that of Adam Thomassone, which was dated 1327, in the Subsidy Rolls of Derbyshire, during the reign of King Edward 111, known as "The father of the English navy", 1327 - 1377.