This interesting surname has a number of possible sources. Firstly, the surname may be of Norman origin, introduced into England after the Conquest of 1066. It may derive from the Old French personal name "Burdo" (oblique case "Burdon"), probably of Germanic origin, but uncertain meaning. The surname may also be a nickname for a pilgrim or one who carried a pilgrim's staff, from the Old French "bourdon", pilgrim's staff. It has also been suggested that the surname derives from the Old German or Latin "burdo", a mule, and would have been an occupational name for a pack carrier, or indeed a nickname given to a strong person. The creation of surnames from nicknames was a common practice in the Middle Ages, and many modern-day surnames derive from medieval nicknames referring to personal characteristics, as in these instances, the "pilgrim" or "strong one". Finally, the surname may be of Anglo-Saxon origin, and a locational name from Great Burdon (Durham) or Burdon Head (West Riding of Yorkshire), which derive from the Olde English pre 7th Century "burh", fortress, with "dun", hill. Another Burdon in Durham means "valley with a byre", from "byre", byre, with "denu", valley. Ilger Burdun is noted in the Pipe Rolls of Yorkshire (1166), Bruni burdin, in the 1180 Buckinghamshire Pipe Rolls, and Nicholas Burdon in the 1242 Fees Court Rolls of Wiltshire. A Coat of Arms granted to a Burdon family in the reign of Richard 11 (1377 - 1399) depicts, on a blue shield, a semee of gold cross crosslets, and three gold bourdons (pilgrim's staves). The first recorded spelling of the family name is shown to be that of Arnulf Burdin, which was dated 1115, in the "Book of Winton", during the reign of King Henry 1, known as "The Administrator", 1100 - 1135. 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.