The ruling house (in full Orange-Châlons) of the principality centred on the small city of Orange, southern France. The city grew up around its Roman monuments, which include a semicircular theatre and a triumphal arch. In the 11th century it became an independent countship, and from the 12th century its rulers were vassals of the Holy Roman Emperor and came to style themselves ‘princes’.

After 1530 the related house of Nassau-Châlons succeeded to the title, and in 1544 William of Nassau-Dillenburg (1533–84) became Prince of Orange and subsequently, as William I (the Silent), statholder in the Netherlands. His younger son, Maurice of Nassau (1567–1625), assumed the military leadership of the Dutch Revolts in 1584. Until the late 18th century the Orange dynasty continued to play a major part in the politics of the United Provinces. The principality itself was conquered by Louis XIV (1672) and incorporated into France by the Treaty of Utrecht (1713), but the title of Prince of Orange was retained by William III, who became King of England, Scotland, and Ireland in 1689.