It was produced long after Richard's death, presumably from an earlier drawing which has not survived. It was intended as a pattern for other artists to follow.
Technical analysis shows that it has been altered, probably in the reign of Henry VIII, and that these alterations were copied in subsequent versions of the painting - including the most famous one, in London's National Portrait Gallery.
These alterations helped to seal the image of Richard III presented by the Tudor historian Sir Thomas More - 'malicious, wrathful, envious, and from afore his birth ever forward' - and represent the solidification of 'Shakespeare's Richard III' in both the royal and popular imagination.