The first Lithuanian rulers did not leave behind any written documents, so we do not know their native titles, but only those given to them by their neighbors. In
Kievan Rus', they were called
knyaz (
kniaz’) or grand knyas (
velikii kniaz’), while in the German sphere they were referred to as elder (
senior), leader (), and sometimes prince (). After the coronation Mindaugas adopted royal title: "By the Grace of God, King of the Lithuania" (). The first mention of a Lithuanian king predates the
establishment of the Christian kingdom itself: according to the
Livonian Rhymed Chronicle, Mindaugas' father was a great king who "had no equal in his time." As the territory of Lithuania expanded eastwards, other king-titled grand dukes who ruled the country adopted similar titles for introducing themselves abroad. For instance, Grand Duke of Lithuania
Vytenis was sometimes regarded as ('King of Lithuanians') while his successor Gediminas was known by the title, in ('King of Lithuanians and many
Ruthenians'). Some German sources also titled Gediminas as ('King of
Aukštaitija'). Gediminas' right to use the Latin
rex, which the papacy had been claiming the right to grant from the 13th century onwards, was not universally recognized in Catholic sources. Thus, he was called
rex sive dux ("King or Duke") in one source;
Pope John XXII, in a letter to the King of France, referred to Gediminas as "the one who calls himself
rex". However, the Pope did call Gediminas
rex when addressing him (
regem sive ducem, "king or duke"). with his title (in
Latin) as 'King in Lithuania', used in 1377–1386, before becoming the
King of Poland in 1386
Teutonic knights referred to
Algirdas and his wife
Uliana (
Julijona) as "Grand King of Lithuania" and "Grand Queen of Lithuania". In early 2000s a plaque with a mysterious script, dating to the 13th–14th centuries, which was nailed to a wooden base, was found during an archeological research in the Courtyard of the Old Arsenal of the
Vilnius Castle Complex, part of which is translatable from the
Ancient Greek as
Algirdos Basileus (a Greek term
Basileus means a 'king' or an '
emperor'). In 1370, Algirdas wrote a letter to the
Ecumenical Patriarch of Constantinople where he titled himself as
Basileus, showcasing his status as an equal sovereign ruler to the
Byzantine Emperor. Even though it is traditionally accepted that Mindaugas was the only true king, all historical records, with the exception of Slavic annals, mention Lithuanian rulers as kings until 1386.
Grand Duke Officially, the title of Grand Duke of Lithuania (
Magnus Dux Lithuaniae) was introduced after the
Pact of Horodło in 1413. Vytautas the Great gained the factual rule of Lithuania, which was recognized by the treaties. Jogaila's son
Władysław III also titled himself as the Supreme Duke of Lithuania. ==Inaugurations of Lithuanian monarchs ==