County_of_Mark--King_of_Prussia_Frederick_II

The County of Mark (German: Grafschaft Mark, French: Comté de La Marck colloquially known as Die Mark) was a county and state of the Holy Roman Empire in the Lower Rhenish–Westphalian Circle. It lay on both sides of the Ruhr River along the Volme and Lenne rivers.
The Counts of the Mark were among the most powerful and influential Westphalian lords in the Holy Roman Empire. The name Mark is recalled in the present-day Märkischer Kreis district in lands south of the Ruhr in North Rhine-Westphalia, Germany. The northern portion (north of the Lippe river) is still called Hohe Mark ("Higher Mark"), while the former "Lower Mark" (between the Ruhr and Lippe Rivers) is for the most part merged in the present Ruhr area.