He that thinks absolute power purifies men's blood, and corrects the baseness of human nature, need but read the history of this, or any other age, to be convinced to the contrary.
Gist of Idea
The idea that absolute power improves mankind is confuted by history
John Locke (Second Treatise of Government , 092)
I can't imagine who proposed the view that Locke is attacking, but it will have been some real 17th century thinker. Attitudes to monarchy changed drastically in England, but Louis XIV was still ruling in France.
Locke,John: 'Two Treatises of Government' [Everyman 1988], p.162