The Treaty of Berum was a treaty concluded on 28 January 1600 at Berum Castle, Berum, between the Count Enno III of East Frisia and the County of Rietberg, which regulated the sale of the Harlingerland to East Frisia.
With the death of Balthasar Oomkens von Esens in 1540, the Attena line of East Frisian chieftains ruling Harlingerland died out and the Harlingerland fell to the Counts of Rietberg, who were related to the Attenas. From 1540, Harlingerland was ruled by Count John II of Rietberg, the son of Balthasar's sister. After his death, the Harlingerland went to his second daughter, Walburgis. She married in 1581 Count Enno III of East Frisia. They had two daughters, who, by the Treaty of Berum, waived their right to inherit Harlingerland, in favour of Enno's son Rudolf Christian, from his first marriage.
Sabine Catharine and her sister Agnes sold the Lordships of Esens, Stedesdorf and Wittmund and thus the entire Harlingerland, to their father, for 200000talers. The payment was later increased to 300000talers. Sabina Catherine, the elder sister, would inherit the county of Rietberg. The Treaty was confirmed on 19 September 1600 by Emperor Rudolph II and later also by Archduke Albert, who was nominally Duke of Guelders and thereby liege lord of the Harlingerland.
In 1622 Ernst von Mansfeld stole the 300000talers, packed in barrels, which Enno III had prepared as payment for Agnes and her husband Prince Gundakar of Liechtenstein. So the payment could not be made then.
In 1663, demands for payment were renewed. Since East Frisia under Prince George Christian still could not pay, the liege lord of the County if Rietberg, the Prince-Bishop of Münster, try to collect the debt. He attacked East Frisia and occupied the sconce at Diele. The States-General and Duke Eberhard III of Württemberg intervened. They drove out the Münster troops from Diele and mediated a compromise in which the payment was raised by another 200000talers.
Wittmund is a town and capital of the district of Wittmund, in Lower Saxony, Germany.
Hero Oomkens von Esens was a Frisian nobleman, the Earl of Harlingerland. He inherited the title upon the death of his father, Sibet Attena von Esens, in 1473.
Enno III of Ostfriesland or Enno III of East Frisia was a Count of Ostfriesland from 1599 to 1625 from the Cirksena family. He was the elder son of Count Edzard II of Ostfriesland and his wife Princess Katarina of Sweden, eldest daughter of King Gustav I of Sweden.
Edzard II was Count of East Frisia from 1561 to 1599. He was the son of Enno II of East Frisia and Anna of Oldenburg.
The County of East Frisia was a county in the region of East Frisia in the northwest of the present-day German state of Lower Saxony.
Ulrich I of East Frisia was the first count of East Frisia, from 1408 in Norden to 25 or 26 September 1466, in Emden. He was a son of the chieftain Enno Edzardisna of Norden and Greetsiel, and Gela of Manslagt.
Edzard I, also Edzard the Great was count of East Frisia from 1491 until his death in 1528.
Enno II of East Frisia was the son of Edzard I of East Frisia. In 1528 he became count of East Frisia. For most of his life he ruled together with Johan I of East Frisia, who remained Catholic, while Enno was Lutheran.
Anna of Oldenburg was a Countess consort of East Frisia as the spouse of Count Enno II of East Frisia. She was the Regent of East Frisia in 1542–1561 as the guardian for her minor sons, Johan II and Edzard II. Her reign lasted until 1561 and was generally supported by the Estates.
The House of Cirksena was the ruling family of East Frisia. They descended from a line of East Frisian chieftains from Greetsiel.
George Christian was a member of the Cirksena family and succeeded his brother Enno Louis as ruler of East Frisia. He ruled from 1660 to 1665. Under his reign, the Cirksena family acquired on 18 April 1662 the hereditary title of Imperial Prince.
Prince Christian Everhard of East Frisia was a Prince of East Frisia from the House of Cirksena from the day he was born in 1665, but remained under guardianship until 1690.
Enno Edzardisna was a chieftain of Norden, Greetsiel, Berum and Pilsum in East Frisia. He was the son of the chieftain Edzard II of Appingen-Greetsiel and his wife Doda tom Brok. Enno was a pioneer of the claim of the house Cirksena to the rule over all of East Frisia, which his son finally Ulrich I formally achieved when he was made an Imperial Count in 1464.
Countess Walburgis of Rietberg was 1565–1576 and 1584–1586 Countess of Rietberg.
Berum Castle is located in the Berum district the East Frisian town of Hage in Germany. It is one of the most important sites in East Frisian history.
John III of Rietberg was a member of the Cirksena family. He founded the Catholic side line of the Cirksena in the Westphalian County of Rietberg, the so-called house of East Frisia.
Sabina Catharina of East Frisia was a Countess of Rietberg in what is now Germany.
Count John II "the Mad" of Rietberg, called "the Great," was the son of Count Otto III of Rietberg and his second wife, Onna Esens.
Eric V of Hoya was from 1563 to 1575 Count of Hoya.
Count Otto III Rietberg was Count of Rietberg from 1516 to 1535.