Antonio Soler (baptized Dec. 3, 1729, Olot, Spain—died Dec. 20, 1783, El Escorial Monastery, near Madrid) was the most important composer of instrumental and church music in Spain in the late 18th century.
Soler was educated at the choir school of Montserrat and at an early age was made chapelmaster at Lérida Cathedral. In 1752 he joined the Order of St. Jerome (Hieronymites) and became organist at the Escorial Monastery. As one of the most notable keyboard performers of his time, he taught both organ and harpsichord to members of the royal family. He was himself a student of Domenico Scarlatti, whose influence may be perceived in the lively keyboard technique, the form, and the frequently unexpected harmonic progressions of Soler’s numerous harpsichord sonatas and also in some of his organ works. He wrote much church music, in which he often indulged a taste for intricate canons; incidental music for plays by Calderón and others; six quintets for organ and strings; and six concerti for two organs. He also wrote a work on musical theory, Llave de la Modulación (1762), which was the subject of significant controversy among his contemporaries. His experiments with microtones led him to invent, for the purpose, a keyboard instrument called the afinador.