Ensemble XXI was founded in 1989 in Moscow as the first professional orchestra in Russia with international membership. It was founded by the Irish Conductor, Lygia O’Riordan and the Finnish Violinist, Pia Siirala, during their studies at the Moscow Tchaikovsky Conservatory with Professors Gennady Rozhdestvensky and Zorya Shikhmurzayeva respectively.

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. For this reason Ensemble XXI was not able to continue working in Russia. In 2022, Ensemble XXI continued its activities in Kosovo. This was made possible by the distinguished Kosovan Violinist, Professor Sihana Badivuku who was one of the founding members of Ensemble XXI in Moscow.