Pierre-Louis-Philippe Dietsch was a French composer and operatic conductor. He is thought to have started his music career as a choir boy at Dijon Cathedral, though by 1822 he is known to have pursued studies in Paris at Alexandre-Étienne Choron's Institution Royale de Musique Classique et Religieuse. In 1830, he became a student of Antoine Reicha in counterpoint, and took up the double bass. In 1840, on a recommendation from Rossini, Dietsch assumed duties as chorus master at the Paris Opera and was promoted to the post of conductor in 1860. From 1853 to 1865, Dietsch also served as an instructor at the successor to Choron's Institution, the École Niedermeyer. He is perhaps best remembered for his opera, Le vaisseau fantôme ou le Maudit de Mers, a work which bears some similarities with Wagner's Der fliegende Holländer, with additional story elements borrowed from Walter Scott and James Fenimore Cooper. His later conflicts with Wagner over the 1861 Paris production of Tannhäuser, and with Verdi over I Vespri siciliani, led to his resignation in 1863. Dietsch was the arranger of a well-known Ave Maria, based on a madrigal by Arcadelt.