The statue was famously as unpopular as the king himself with Parliamentarians during the Civil War. It was given to a brazier named John Rivet for melting down - but instead he buried it, ensuring its survival until the Restoration. However, he didn't lose out by this gesture - while the statue was lying out of sight, he made plenty of money selling knives and forks whose handles were supposedly made from its brass.
It has sat on its current site since 1671. Although rich in history, I like it for a more frivolous reason - this must be the most alarmed-looking horse in London!