Gustav Maria Leonhardt was one of the best-known leaders of the Early Music movement. A harpsichordist and organist and later a conductor, he was credited with being one of the most important figures in establishing the Netherlands as one of the main centers of period music performances.

He had a classical education, then entered the Schola Cantorum in Basle. There he studied organ and harpsichord with Eduard Müller. In 1950 he made his debut in Vienna with a harpsichord performance of J.S. Bach's cerebral masterwork, The Art of the Fugue. He studied musicology in Vienna for a year, then took a position as professor of harpsichord at the Vienna Academy of Music (1952-1955).

In 1954 he became professor of harpsichord at the Amsterdam Conservatory and at the same time organist of the historic Waalse Kerk (Church) there, which has a magnificent Baroque organ built by Christian Müller in 1733.

In 1955 he organized the Gustav Leonhardt Consort, one of the first "period instruments" groups, and one that was a leader in the field for most of its existence. This led to his conducting the ensemble and also choral groups in the Baroque and Classical repertoire, particularly that of J.S. Bach.

His area of specialty included the 17th and 18th centuries. As a musicologist, he did extensive research in the preparation and technique of the instruments, performing styles, ornamentation, and so forth. As a teacher, he inspired such leading Dutch musicians as keyboard player Bob van Asperen, flutist Barthold Kuijken, and cellist Anner Bylsma.

In 1967 he starred in Jean-Marie Staub's motion picture biography of Johann Sebastian Bach, portraying the master and playing his music on organ and harpsichord. In 1967 and 1968 he was a visiting professor at Harvard University.

Leading the Leonhardt Consort, he produced Teldec's great series of complete Bach cantata recordings (sharing the cantatas with Nikolaus Harnoncourt and the Vienna Concentus Musicus). He recorded extensively for that label, shifting to Sony Classics in the 1990s. His performances tended to be restrained, an academic approach that characterized the earliest wave of period music performance, which inspired both followers and a group that reacted against it with lively, more historically speculative performance styles.

Leonhardt was also a respected scholar and editor of Baroque music, especially the music of Sweelinck, and authored a major study of The Art of the Fugue. He has won several honorary degrees and Holland's prestigious Erasmus Prize (1990). ~ Joseph Stevenson, Rovi