This name is of English locational origin from a place thus called in the parish of Millom, Cumbria. The first element is believed to be the Medieval English personal/nickname (A)postle, probably originally given to one who played the part of one of the twelve apostles in a play or pagent, plus the nothern Medieval English "thwaite", a clearing, hence, "Postle's clearing". The surname is first recorded in the latter half of the 15th Century, (see below). One, Richard Postlethwaite recorded in the burial register of Ulverston Church, Lancashire in 1546 and in 1547 William Postlewait and Sebell Asburner were married in the above church. Eminent namebearers were John Postlethwayt (1650 - 1713), M.A. Oxford (1678) and high master of St. Paul's school, 1697 - 1713. Thomas Postlethwaite (1731 - 1798) became master of Trinity College, Cambridge in 1789. The first recorded spelling of the family name is shown to be that of Thomas Postilltwayte, which was dated 1467, in the "Guild Registers of the City of York", during the reign of King Edward 1V, known as "The Self Proclaimed King" 1461 - 1483. 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.