Medieval kings had to meet all their expenses, private and
public, from their own revenue. In times of crisis, the king
would try and persuade his barons to grant aid - but on 
some occasions this was not enough. The Great Council 
therefore began to expand during the 13th Century - to 
include both  barons and church dignitaries (the 
equivalent of today's House of Lords) and representatives 
of the cities, towns, and counties (the equivalent of today's 
Commons). The word Parliament (meaning a meeting for 
parlez or discussion) was first used to refer to this group in 1236.

In 1254, seeking additional aid for 'his great emergency', Henry III instructed the country's sheriffs that the knights who represented the counties were - for the first time - to be elected to the post.