John fought 3 wars with the Electorate of Cologne and finally defeated Ruprecht of the Palatinate, conquering the cities of Xanten and Soest.[2] In these wars, he was supported by his uncle Philip the Good, bringing Cleves-Mark into the Burgundian sphere of influence. His marriage with Elisabeth Countess of Nevers, from a sideline of the House of Burgundy, only strengthened this influence. John also took sides in the Münster Diocesan Feud supporting the aspirations of the House of Hoya to the episcopacy in Münster.[3]
Boltanski, Ariane (2006). Les ducs de Nevers et l'État royal: genèse d'un compromis (ca 1550 - ca 1600) (in French). Librairie Droz S.A.
Boulton, D'Arcy Jonathan Dacre (2000). The Knights of the Crown: The Monarchical Orders of Knighthood in Later. The Boydell Press.
Laffan, R.G.D. (1936). "The Empire in the Fifteenth Century". In Previte-Orton, C.W.; Brooke, Z.N. (eds.). The Cambridge Medieval History: The Close of the Middle Ages. Vol. 8. Cambridge University Press.
Vaughan, Richard (2002). Charles the Bold: The Last Valois Duke of Burgundy. Vol. 4. The Boydell Press.