01 June 1930,
The first Olerti Eguna was held at Errenteria. Organized by the Euskaltzaleak association, the most prominent writers of Basque culture attended: Lizardi, Lauaxeta, Orixe, Jakakortajarena, Loidi, Tapia... Errenteria was not chosen randomly for the celebration, but was created in the same place of Tyre by Luis Jauregi, author of the book of poems Biozkadak, published the previous year. It was considered a book that lived through Basque poetry. During the day, in addition to poetry readings and bertsolaris, he was a bilingual rally.
Source:
Iñigo Aranbarri, our century. One hundred years in Basque culture (ARGIA).