Statehood Day is an annual public holiday in Lithuania celebrated on July 6 to commemorate the coronation

Coronation

A coronation is a ceremony marking the formal investiture of a monarch and/or their consort with regal power, usually involving the placement of a crown upon their head and the presentation of other items of regalia...

 in 1253 of Mindaugas

Mindaugas

Mindaugas was the first known Grand Duke of Lithuania and the only King of Lithuania. Little is known of his origins, early life, or rise to power; he is mentioned in a 1219 treaty as an elder duke, and in 1236 as the leader of all the Lithuanians...

 as the first and only King of Lithuania. The exact day of this event is disputable and was chosen according to the hypothesis of Edvardas Gudavičius

Edvardas Gudavicius

Edvardas Gudavičius is one of the best known historians in modern Lithuania specializing in early history of Grand Duchy of Lithuania. In 1953 he graduated from Kaunas Polytechnic Institute with a degree in engineering. Gudavičius started his career as a mechanic at one of the factories in Kaunas,...

, formulated in 1989. The day has officially been celebrated since 1991.