There is quite a bit of speculation about when spurs were introduced as a horseback riding aid.  The earliest for were most likely made of wood or bone. Once spurs were made of metal tracing their history became a bit easier. The Roman Legions in 100 BC to 44 BC were found to be using spurs. The earliest spurs are pretty much like our English spurs of today in that they did not have rowels. Spurs with rowels were believed to have originated in France or Spain in the 10th century AD. These are the forerunners of the spurs that came to America with the Spanish who arrived in the 1500's. These spurs evolved into the Western spurs that we associated with the cowboy spurs of today. 

Spurs have become very specialized for both English and Western riders. English riders use both short and long neck spurs.The reason has to do with the length of the riders leg and where it will touch the horses flank. Whether for English or Western riding, spurs are meant to be used as an aid in communication with a horse and are not intended to harm the horse.

Western riding covers a somewhat broader range of use. Bull riders actually use the spur to help grip the sides of the bull. Ropers, cutters and reiners all have spurs made to there particular needs. You will also see that each riders personality plays a part in the spur he or she wears. Spurs that exhibit inlay-ed and engraved silver are used on both English and Western Spurs.