Gernikako Arbola

The Lords of Biscay (including kings of Castile and Carlist pretenders to the throne) swore to respect the Biscayan liberties under it, and the modern Lehendakari of the Basque Country swears his charge there.

The known specimens[1] form a dynasty: The Tree of Gernika came to prominence during the First and Third Carlist Wars as a symbol of Basque liberties, whose renown and appreciation spread among the Basque diaspora world over during the late 19th century and mid-20th century thanks to the popularity of Jose Maria Iparragirre's namesake anthem.

Maria Cristina of Savoy, regent during her daughter Isabel's minority in the First Carlist War, swore the Basque charters under the Oak in 1839.

When the Francoist troops took the town, the Tercio of Begoña, formed by Carlist volunteers from Biscay, put an armed guard around the tree to protect it against their Falangist allies, who had wanted to fell this symbol of Basque nationalism.

[2] On 26 June 1950, Xavier of Bourbon-Parma, Carlist claimant to the Spanish throne during Franco's dictatorial regime, swore the Basque charters in the Oak of Guernica.

The "new tree"
The trunk of the "Old Tree"
The oak leaves and acorns around the coat of arms of the Basque Country are another reference to the tree.