^Hayden 1973，p. 22: "The other major problem in the [Holy Roman] Empire brings full circle the discussion of the Regency foreign policy. The two occupants of the Cleves–Jülich territory could not get along with each other. In the involved negotiations, the claimants changed religions and sought outside allies. The result was the threat of war in 1614 by the allies, the Dutch for Brandenburg and the Spanish for Neuberg. These two states, however, had no desire to break the truce of 1609, and after some feinting, negotiations opened which were assisted by England and France. The resulting Treaty of Xanten was signed on November 12, 1614, with Jülich and Berg going to Wolfgang William of Neuberg while Elector John Sigismund got Cleves, Mark, and Ravensburg. The Spanish army under Spinola refused to give up the key fortress of Wesel, and further negotiations were necessary, but in the end a shaky peace was maintained."