As we saw HERE, the power of the vassals in the medieval Kingdom of France began being limited during the reign of Louis VI the Fat.
This process went on for quite a while, until, during the reign of Philip IV the Fair, the power of the vassals was limited as never before whereas that of the medieval French monarchy reached its peak, surpassing even the papacy. Philip's favourite motto was, 'Only God is above the King.'
Regarding Philip's nickname, mind you, fair in this case means beautiful, not just. For, although I don't know whether that guy was beautiful (I'm not attracted to the male gender anyway), one could say he was anything but just.
But let's take things from the top. Philip became a king in 1285. One year earlier, he had married Joan of Navarre, when he was 16 and she was 11. And even though, nowadays, that would be borderline gross and require an FBI alert, by medieval standards, they made a pretty lovely couple whose life could be a fairytale.
Unfortunately, it wasn't. You see, poor Joan died in 1305, with Philip refusing to marry again (for all his flaws, he was a devoted husband!) By that time, Philip had been engaging into various wars.