Shut the stable door after the horse has bolted

This proverb about acting too late or taking pointless precautions after the event, appears in various forms from as early as 14th century. Sometimes the stable door is described as being locked or made secure after the horse has been stolen or has escaped, but the meaning remains essentially the same. It appears in John Heywood's Proverbs (1546) in the form of “When the steed is stolen, shut the stable door.” During the 20th century c. 1940, the expression has been shortened to 'that horse' or 'the horse' has bolted, without any reference to the stable, meaning that it is now too late to do anything to affect or alter the situation.