Roman Catholic Diocese of Dorpat

Bishopric of Dorpat
Bisdom Dorpat (nds) Ecclesia Tarbatensis (la)
Prince-Bishopric of Terra Mariana
1224–1558
Coat of arms
The Bishopric of Dorpat, shown (orange, upper right) within the Livonian Confederation, 1260
Capital		Dorpat (Tartu), from 1224
Languages		Low German, Estonian
Religion		Roman Catholicism
Government		Theocracy
Prince-Bishop
•	1224–48	Hermann von Buxhövden
•	1552–60	Hermann Wesel
Historical era		Middle Ages
•	Established	1224
•	Henry VII grants margraviate	1 December 1225
•	Livonian War	1558
Preceded by Ugaunia

The Bishopric of Dorpat (Estonian: Tartu piiskopkond; Low German: Bisdom Dorpat; Latin: Ecclesia Tarbatensis) was a medieval prince-bishopric, i;e; both a diocese of the Roman Catholic Church and a temporal principality ruled by the bishop of the diocese. It existed from 1224 to 1558, generally encompassing what are now Tartu County, Põlva County, Võru County, and Jõgeva County in Estonia. The prince-bishopric was a sovereign member of the Holy Roman Empire (formally from 6 Nov 1225) and part of the Livonian Confederation.

The first Bishop of Dorpat (the current Tartu) was Hermann von Buxhövden, the brother of Albert von Buxhövden, Bishop of Riga and leader of the Livonian Crusade. The Estonian Diocese was established by the Bishop of Riga in 1211 and its first nominal seat was Leal (Lihula) in western Estonia. In 1224, Bishop Hermann took possession of parts of what is today southeastern Estonia and chose Dorpat as his new seat. On 6 November 1225 he was enfeoffed with his principality by Henry VII of Germany, King of the Romans, and on 1 December Dorpat was created a March of the Holy Roman Empire. The principality was founded mainly on territories of the Ugaunian tribe of ancient Estonians. In 1242, Bishop Hermann with his Ugaunian subjects was defeated by Novgorod's prince Alexander Nevsky in the famous Battle on Lake Peipus.