The Bishopric of Reval was a Latin Church ecclesiastical territory or diocese of the Catholic Church in Reval, Duchy of Estonia created by Valdemar II of Denmark in 1240. Contradictory to canon law, Valdemar II reserved the right to appoint the bishops of Reval to himself and his successor kings of Denmark. The decision to simply nominate the see of Reval was unique in the whole Catholic Church at the time and was disputed by bishops and the Pope. During the era, the election of bishops was never established in Reval and the royal rights to the bishopric and to nominate the bishops was even included in the treaty when the territories of the Duchy of Estonia were sold to Teutonic Order in 1346.