Enno III, Count of Ostfriesland

Enno III
Count of East Frisia
Enno III, Count of East Frisia
Reign	1599–1625
Predecessor	Edzard II
Successor	Rudolf Christian
Born	(1563-09-30)30 September 1563 Aurich
Died	19 August 1625(1625-08-19) (aged 61) Leerort
Spouse	Walburgis, Countess of Rietberg Anna of Holstein-Gottorp
House	Cirksena
Father	Edzard II
Mother	Katarina of Sweden

Enno III of Ostfriesland or Enno III of East Frisia (30 September 1563, Aurich – 19 August 1625) 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.

In 1602 Enno III's troops laid siege to Emden, without success; On 8 April 1603 Enno had to sign the Treaty of 's-Gravenhage in which he not only accepted the presence of a Dutch garrison in Emden, but agreed to pay the costs for the Dutch garrison. In 1609 the conflict broke out again; the Emders were victorious in a skirmish at Greetsiel and temporarily occupied the Count's residence at Aurich. In 1611 the Dutch garrisoned troops in Leerort. On 24 May the Accord of Osterhusen was signed, which limited the sovereignty of the Count of East Frisia, stated the rights of the Estates (including Emden) and legitimised the Dutch garrison in Leerort.

Enno III was married twice. Firstly, he married Countess Walburgis of Rietberg (1556–1586), daughter and heiress of Count John II of Rietberg, Lord of Esens, Stedesdorf and Wittmund and Countess Agnes of Bentheim-Steinfurt. Countess Walburgis, a descendant of Hero Oomkens von Esens, brought the estates of Harlingerland and Rietberg to East Frisia. They had three children:

Countess Walburgis of Rietberg died only few days after her son. Allegedly she was poisoned. Stine Essken was burnt at the stake for this. After the male line of the counts of Rietberg became extinct, the counts of East Frisia became their successor due to the marital connection of Enno III with Walburgis.