Ensemble Ursa Major is dedicated to the exploration, performance, and study of music composed before 1600. Founded in 2022 by Leah Weitzner, Ellis Reyes Montes, and Namgon Lee, while pursuing graduate studies in musicology and historical performance at McGill University, the ensemble brings together scholarly precision and artistic imagination in its approach to medieval music.

Respected professionals, including Esteban La Rotta, Rebecca Bain, and Ensemble Diabolus in Musica and La fonte musica guided their formation. Ensemble Ursa Major will be a featured ensemble in Early Music America's 2026 Emerging Artists Showcase, has been a featured ensemble in Les Reverdies de Montreal’s Journées Médiévales 2023, and was recipient of the 2024 Early Music America’s Encouragement Award.

Leah Weitzner is a soprano, gambist, and researcher. She graduated from McGill University in 2021 with a B.Mus. in Early Music Vocal Performance and recently completed an M.A. in Musicology at McGill, under the supervision of Professor Julie E. Cumming. Her thesis explores poet-improvisation in the anonymous musical settings of Serafino Aquilano's strambotti. She is a co-founder of the vocal trio Ensemble Increatum, and she collaborates frequently in Montréal with early and contemporary music ensembles. In 2025, she received the Barbara Thornton Memorial Scholarship from Early Music America.

C. Ellis Reyes Montes is an accomplished musician and writer who has performed and presented around the world. A recipient of the 2025 Thomas Zajac Memorial Scholarship, FRQSC Doctoral Grant, and the RIdIM Young Scholars Encouragement Award, he is a PhD candidate in musicology at McGill University, researching pipe and tabor in the Viceroyalty of Perú in the 16th-18th centuries. A fourth-generation musician and scholar of performance practice, he performs historical and traditional music around North America with a variety of wind instruments, including the bassoon, oboe, pipe and tabor, recorder, panpipes, and quena. 

Dr. Namgon Lee is a violist, composer, and researcher specializing in historical performance. His study focuses on expanding early viola literature through the performing-composer traditions. He has performed with leading period ensembles including Ensemble Caprice and Arion Baroque Orchestra, and is a founding member of the award-winning Ximenez Quartet and Ensemble Ursa Major. Namgon won First Prize in the 2024 David Dalton Viola Research Competition and was named an emerging artist and scholar at the 2024 and 2026 American Viola Society Festivals. Dr. Lee holds degrees from the Manhattan School of Music, the Peabody Institute, and McGill University.