Jan Josef Ignác Brentner (Johann Joseph Ignaz, surname also spelled Brenntner, Brendner, Brendtner, or Prentner; 3 November 1689 – 28 June 1742) was a Bohemian composer of the Baroque era.
Jan Josef Ignác Brentner was born into the family of the mayor of the town of Dobřany in Western Bohemia. He seems to have preferred his middle name Josef/Joseph. What we know about him comes mostly from time he spent in Prague, from 1717 to about 1720, where he published four collections of music. Brentner's opuses 1 and 3 are collections of sacred arias for voice, strings, and continuo, Harmonica duodecatomeria ecclesiastica (1716) and Hymnodia divina (1718 or 1719). In addition, Brentner published a collection of six offertories for chorus, strings, and continuo entitled Offertoria solenniora (1717) as his opus 2 and a collection of six chamber concertos, Horae pomeridianae seu Concertus cammerales (1720) as his opus 4. Brentner's patron was Raymond Wilfert, abbot of the Premonstratensian (Norbertine) monastery in Teplá, to whom the Op. 2 was dedicated. Brentner's funeral motets were written specifically for the Brotherhood of St. Nicholas Church in Prague. Brentner died in his home town of Dobřany.
Although a great many of Brentner's works are known to be lost, a scattering of manuscript copies survive throughout the Czech lands and a large number of them are located in the Music Archive of the Bendiktinerstift in Göttweig, Austria. Still others have turned up, in modified versions, in Bolivia; no one knows how Brentner's music managed to travel to South America. Registries of lost collections belonging to provincial churches in central Europe bear witness to Brentner's works that are no longer extant.
Brentner's music fuses a simple and direct melodic component with a complex and highly ornamented instrumental accompaniment. Although Brentner has never been a famous name, his music has proved enduring—it was still being performed in Prague and Vienna (Hofkapelle) in the mid-nineteenth century, and they have never stopped playing it in Bolivia.