To what extent was Spain a united and well governed country during the reign of Charles V?

Charles ascended the Spanish thrones of Castile and Aragon at the age of 16 after the death of his grandfather Ferdinand in 1516. He ruled there until his abdication in 1556, at the age of 56, a period of forty years. For most of this time he was the undisputed king of Castile and Aragon and he also held other territories such as the Holy Roman Empire, the Habsburg lands and the Netherlands. Naturally, the long period of time meant that his method of ruling changed during his reign His ‘ownership’ of lands other than those in Spain was a problem as it meant he would have to be an ‘absentee monarch’. Charles inherited a kingdom that was no more united by 1516 than it had been at the beginning of the joint reigns of Isabella and Ferdinand, and when he abdicated Castile and Aragon were still two separate states.