This interesting surname is of Old French origin, introduced into England after the Conquest of 1066, and has two possible sources. Firstly, the surname may be an occupational name for an innkeeper, deriving from the Old French "(h)ostelier", Middle English "(h)osteler". This term was at first applied to the secular officer in a monastery who was responsible for the lodging of visitors, but it was later extended to keepers of commercial hostelries, and this is probably the usual sense of the surname. The surname may also derive from the Old French "oiseleor, "oiseleur", bird-catcher, fowler, or "oiselier", seller of game, poulterer. Job-descriptive surnames originally denoted the actual occupation of the namebearer, and later became hereditary. The surname is first recorded in the latter half of the 12th Century (see below), and has many variant spellings ranging from Ostler, Horsler and Hustler to Oslar and Hosler. Edid le Osteler was a witness in the Assize Court Rolls of Staffordshire (1204), and Alberic le Oselur is noted in the Feet of Fines, Cambridgeshire (1208). Recordings of the surname from London Church Registers include: the marriage of Ann Osler and John Whighthed on October 23rd 1586 at Allhallows, Honey Lane; and the christening of Thomas, son of Thomas Osler, on March 31st 1639 at St. Margaret's, Westminster. The first recorded spelling of the family name is shown to be that of William Osselur, which was dated 1170, in the "Pipe Rolls of Yorkshire", during the reign of King Henry 11, known as "The Builder of Churches", 1154 - 1189. 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.