Because Charles V needed to consolidate the Spanish throne and manoeuver to become Holy Roman Emperor, he lifted the Imperial ban against Edzard and invested him with East Frisia, thereby ending the Saxon feud. He also made peace with Charles II, Duke of Guelders, leaving him in control of most of Friseland, the Ommelanden and Groningen. Edzard was thus forced to vacate Groningen and to give up his expansionist plans. Domestically, he was busy trying to pacify the East Frisian chieftains. On 3 December 1517, Edzard concluded the Peace of Zetel with Henry II, Duke of Brunswick-Wolfenbüttel and John V, Count of Oldenburg, in which he ceded the "Frisian Forest" (The area around Zetel, Driefel and Schweinebrück) to Oldenburg. The city of Aurich was completely destroyed during the turmoil of the Saxon feud. After 1517, the city was rebuilt according to a plan, which was based on the fact that Aurich was an important livestock market. The emperor had invested Edzard with the Harlingerland and Edzard tried to subdue it. However, due to well-constructed fortifications at Wittmund and Esens, he met with limited success.