Ensemble XXI was founded in 1989 by Irish Conductor Lygia O’Riordan and Finnish Violinist Pia Siirala after completing their studies at the Moscow Tchaikovsky Conservatory. Ensemble XXI in its foundation, membership and activity is living proof of the capacity of music to bring together people of diverse backgrounds and origins on a plane of understanding, which recognises no borders.

The orchestra has toured to the world’s greatest concert halls from Vienna to Sydney.
Ensemble XXI also brings music to remote communities the world over. Of particular importance is the orchestra's ongoing work to highlight the ancient music of the Arctic’s indigenous communities.