Distinguished violinist and teacher; born at Bellaire, near Liege. When about nine years old he received his first instruction from a violinist named Rouma. The wife of a Brussels merchant took an interest in his playing and gave him funds with which to enter the Paris Conservatory. He was seventeen at the time, thus being older than most musicians at entering. Here he studied under Habeneck. In 1844 he made a brilliant tour through Germany, being the first to play Mendelssohn's Violin Concerto in Berlin, under the immediate direction of the composer. Upon Mendelssohn's advice he seriously took up composition. Leonard played in Dresden, Berlin and other capitals in 1846 and the next year traveled in Sweden. This same year he was appointed successor to De Beriot as first professor of violin at the Brussels Conservatory, which position he held until 1867, when he resigned on account of ill health and went to live in Paris. He died in Paris. His greatest fame was earned as a teacher. He had many pupils, possibly the most celebrated of whom is Martin Marsick. Among his compositions are a number of violin concertos, studies for the violin, eleven fantasias, two elegies, many operatic fantasias and salon pieces, many of which he wrote in conjunction with the pianist, Joseph Gregoire, duets for violin and cello written with Servais, etc.