An anti-king, anti king or antiking (German: Gegenkönig, French: antiroi, Czech: protikrál) is a would-be king who, due to succession disputes or simple political opposition, declares himself king in opposition to a reigning monarch. The term is usually used in a European historical context where it relates to elective monarchies rather than hereditary ones. In hereditary monarchies such figures are more frequently referred to as pretenders or claimants.
^OED "Anti-, 2" The OED does not give "anti-king" its own entry, unlike "antipope", but includes it in a list of political "anti-" formations, such as "anti-emperor" and "anti-caesar". The earliest example of anti-king cited is from 1619 (and the next by Dr Pusey). Only the hyphenated form is cited or mentioned.
Heinrich Mitteis: Die deutsche Königswahl. Ihre Rechtsgrundlagen bis zur goldenen Bulle, 2nd expanded edition, Rohrer, Brünn, Munich, Vienna, 1944, pp. 113 ff.
Dietmar Willoweit: Deutsche Verfassungsgeschichte. Vom Frankenreich bis zur Wiedervereinigung Deutschlands, 5th revised edition, expanded with a table of chronology and an attached map, Beck, Munich, 2005, pp. 71 f., 94 ff., ISBN 3-406-52637-3
Gerhard Theuerkauf: Gegenkönig. In: Handwörterbuch zur deutschen Rechtsgeschichte, 2nd, fully revised and expanded edition. Published by Albrecht Cordes, Heiner Lück, Dieter Werkmüller and Ruth Schmidt-Wiegand as philological advisor. Edited by: Falk Hess and Andreas Karg, Vol. I: Aachen-Geistliche Bank, Erich Schmidt Verlag, Berlin. 2008, Sp. 1995-1996, ISBN 978-3-503-07912-4