

Siia projekti soovime Genist kokku koguda Eestimaa (ja Liivimaa) hertsoge, kes valitsesid Eestimaa hertsogkonna üle.
The aim of the project is to collect here the links to Estonian (and Livonian) dukes, who ruled over the Estonian Duchy.
Eestimaa hertsogi tiitel oli Eestit valitsenud riikide valitsejate tiitlistikku kuuluv titulaartiitel.
Esimeseks Eestimaa hertsogiks nimetas Taani kuningas Valdemar II aastal 1220 oma poja Knudi.
Eestimaa hertsogi tiitel kuulus ka aastatel 1271–1346 Taani kuningakojale.
Pärast Eesti vallutamist rootslaste poolt 1584 hakati Eesti ala nimetama Eestimaa kubermanguks, vahel ka Eestimaa hertsogkonnaks või Eesti vürstkonnaks, sest Rootsi kuningakojale läks üle ka titulaartiitel Eestimaa hertsog.
Pärast Uusikaupunki rahu sõlmimist aastal 1721 läks Vene keisrikojale üle ka tiitel Eestimaa hertsog. Viimane Eestimaa hertsog oli Nikolai II. Pärast tema troonist loobumist esitati uueks hertsogiks Mecklenburgi hertsog Adolf Friedrich, kuid Esimese maailmasõja lõpu tõttu ei pääsenud ta kunagi valitsema.
The first Duke of Estonia (Danish: Hertug af Estland ) was appointed in 1220 by Valdemar II after Danish conquest of Estonia during Livonian crusade. The title was resumed by the kings of Denmark since 1269. For the period of 1266-82 during the reign of Queen Dowager Margaret Sambiria the title Lady of Estonia (Latin: Domina Estonie) was used.
In 1332 after Christopher II died his elder son Otto inherited the title of the Duke of Estonia. Valdemar III assumed the title in 1338.
The Duke of Estonia rarely resided in Estonia. To govern the Duchy of Estonia the king of Denmark appointed together with royal counsellors the Lieutenant (Latin: Capitaneus) who resided in Reval.
The king of Denmark sold the Duchy to Teutonic Order in 1346 but Christian I re-assumed the title of duke of Estonia in 1456.
After the Livonian War Estonia became part of Swedish Empire and the title was gained by kings of Sweden. Crown Prince Gustav Adolph was Duke of Estonia 1607-1611 before he became King, but then officially abolished all Swedish duchies in 1618.
The title was resumed by the Russian tsars after the Great Northern War and Treaty of Nystad when Estonia became part of Russian Empire. The last Duke of Estonia (Russian: Князь Эстляндский) was Nicholas II of Russia.
After the Russian revolution of 1917 the Soviet Russia had formally relinquished all authority over its former Imperial Baltic provinces to Germany in the Treaty of Brest-Litovsk and the Duchy of Courland was nominally recognized as a sovereign state by Kaiser William II on September 22, 1918. A temporary Regency Council (Regentschaftsrat) for the all Baltic provinces led by Baron Adolf Pilar von Pilchau was formed on November 5, 1918. It was to be a confederation of seven cantons: Kurland (Courland), Riga, Lettgallen (Latgale), Südlivland (Vidzeme), Nordlivland (South Estonia), Ösel (Saaremaa), and Estland (North Estonia). The capital of the new state was to be Riga. The proposed United Baltic Duchy was to be located at the future territory of Latvia and Estonia covering the territory of the medieval Livonian Confederation. The first head of state of the United Baltic Duchy was to be Adolf Friedrich, but he never assumed office. The appointed Regency Council consisting of four Baltic Germans, three Estonians and three Latvians functioned until November 28, 1918, without any international recognition, except from Germany.
Instead of that a democratic Republic of Estonia was established on the territories of historic Estland and North Livland which was proclaimed already in February 24th, 1918 and recognized by Soviet Russia in Tartu Peace Treaty in February 2nd, 1920.
Part of the Danish kingdom
Ruled by the Livonian Order
Part of the Swedish kingdom
Part of the Russian empare
The United Baltic Duchy