Peter I's War (Sedunnic: Peter 1' Ramm; Ezervölgyi: I. Péter háborúja) or Winter War (Sedunnic: Kodlussrammd; Ezervölgyi: Téli háború) was the culmination of several years of deteriorating Sedunno-Ezervölgy relations and an attempt by the latter to replace the democratically elected Sedunnic government with constitutional monarchy and a leadership more favourable to Peter I's regime. Hostilities began in 28 December 1884 and ended with the armistice of 31 February 1885 after Sedunnic troops had seized Fehérvár. The war ended formally 3 May with the conditional surrender of Peter I and the signing of the Treaty of Kodull. The war still remains a sensitive subject in Sedunno-Ezervölgy relations.
