Unofficial Basque Anthem - Gernikako Arbola

"Gernikako Arbola" is a song in bertso form written by José María Iparraguirre, a Basque bard, in the mid-19th century. It celebrates the Tree of Gernika and Basque liberties and has become an unofficial anthem of the Basque people, alongside "Eusko Abendaren Ereserkia." The song's popularity grew during the pro-fueros movement in the run-up to their suppression in 1876, and it became a symbol of political unrest. It quickly spread to the French Basque Country, where it was popularized by the Lore Jokoak festivals.

The song was sung at the end of a demonstration in Pamplona in 1893, after widespread indignation sparked at the Spanish government's breach of fiscal terms concerning Navarre. The anthem was often performed by prominent musicians such as Pablo de Sarasate and Julián Gayarre and has been called the "Marseillaise of the Basques."

In 2007, the General Assembly of Biscay declared "Gernikako Arbola" the district's official anthem. The Tree of Gernika has also inspired a passage of Tirso de Molina's La prudencia en la mujer and a sonnet by William Wordsworth.

"Gernikako Arbola" is a powerful symbol of Basque identity and resistance, and its popularity and significance have only grown over time.