By the middle of the 16th century the Netherlands consisted of some twenty principalities and lordships, loosely connected under the rule of Emperor Charles V. The heir of the dukes of Burgundy, Charles ruled these lands as his own patrimony. They roughly covered the area of the present-day Netherlands, Belgium, and Luxembourg, as well as a strip of northern France. During the rule of Philip II, king of Spain (r. 1555–1598), Charles’s son and successor, a revolt broke out. From c. 1580 onward Philip succeeded in bringing the southern provinces of the Netherlands (roughly modern-day Belgium) back to obedience, while the northern provinces (roughly the area covered by today’s Netherlands) retained their independence. The northern provinces came to be known as the “United Netherlands” or the “Dutch Republic,” the southern ones as the “Spanish Netherlands.” What had begun as a rebellion turned into regular warfare between the Dutch Republic, on the one side, and Spain and the Spanish Netherlands, on the other. The so-called Twelve Year Truce interrupted the fighting between 1609 and 1621. It was not until 1648 that the belligerents finally concluded peace. After 1585 (the capture of Antwerp by the Spanish army), the Dutch Republic and the Spanish Netherlands gradually drifted apart as they became two separate states, and, even more slowly, they developed their own national cultures and identities. The consequence for historiography is that the history of the Netherlands until the end of the 16th century is best studied as a whole, while the histories of the Dutch Republic and the Spanish Netherlands during the 17th century are usually studied separately.