It happened today - October 13, 2015
On October 13 of 1399 King Henry IV of England was crowned. Which might not strike you as especially important unless you are from the 14th or 15th century. But you are.
Henry was the first king from the House of Lancaster, all Henries, ruling successively, and coming a cropper in the Wars of the Roses partly because Henry VI was mad much of the time. So much for historical dust. Now for the good stuff.
Henry is important first because he succeeded Richard II who was deposed for claiming his word was law, that is, for trying to discard the rights of the English, most especially that they controlled their government and not the reverse. It was a rule all but the most reckless would observe; when Henry VI was in exile in France between his first and second unhappy periods of rule, his Chancellor Sir John Fortescue wrote De laudibus legum Angliae (In Praise of the Laws of England) in which he stressed that the common law bound rulers in England, a statement that would not merely have been incorrect elsewhere but incoherent as there was no common law or law of the land elsewhere).
Second, when Henry of Bolingbroke put forward his claim to the throne as Henry IV, it was to Parliament that he had to appeal for confirmation of his status. And Parliament told him that they would confirm him as king only with conditions, which shows a difference between England and places where such an act, if it happens at all, is a formality.
So do the conditions, the most important of which was that whereas in the past Parliaments had been summoned because the king needed money, had presented him with petitions or lists of grievances requesting royal redress, had given him money, and had been sent away again, from now on the king must answer their grievances before he saw a shilling of public money.
It was not the final and complete assertion of the power of the purse; there were many procedural questions to be settled concerning how parliaments would meet, the impunity of their members and so on, and some of these would require an English Civil War and an American Revolution. But others, frankly, have become unsettled again in our own day, with tame legislatures performing circus tricks at the behest of an executive swollen with pride. So let us not be smug about our superiority to those who, in 1400, told the new king that his position on the throne depended not on brute force or royal favour but on respecting the rules against taxation without representation.