Composer, musicologist, arts administrator, and organist Thomas Daniel Schlee has passed away. He was 68.

Schlee was born on Oct. 26, 1957 in Vienna, Austria. His family was heavily involved in music and music publishing. Schlee studied organ at the Vienna Music Academy, where he attended Olivier Messiaen’s last composition class in Paris. He continued his studies in musicology and art history at the Vienna University, earning a PhD in 1984.

Schlee began his career as a music dramaturge at the Salzburger Landestheater in 1986. He went on to teach at the Vienna Music Academy and at the institute of musicology at the Salzburg University. In 1990, he began his role as music director at the Brucknerhaus in Linz and artistic director of the Brucknerfest, where he stayed for nearly a decade. During this time he also worked as musicologist for the Guardini Foundation, where he helped develope the international project, “La Cité céleste,” dedicated to Messiaen’s work. This project included exhibitions, concerts, competitions, a monograph, lectures, and symposia in 15 European cities. Following this, Schlee took on the role of president of the Guardini Foundation, and from 2004 to 2011 headed its advisory committee for music.

During his time as Intendant of the Carinthischer Sommer festival from 2004 to 2015, Schlee expanded the number of venues and continued a tradition of church operas which opened possibilities for several composers to have their works premiered. He was also a member of the university committee of the Mozarteum in Salzburg from 2008 to 2013. In 1990, Schlee was named Chevalier of the Order of Arts and Letters.

Schlee wrote works for various instruments. His vocal music ranged from solos to orchestral works for voice, and choral pieces. Many of his works are recorded with labels such as Weinberg Records.

Schlee died unexpectedly on Nov. 10.