Content Abstract: John Mathias Steinfeldt, known as the Dean of Texas Pianists, was a composer, pianist and organist and a Master-teacher. In San Antonio, he served as organist at the First Baptist church, San Fernando Cathedral and at Temple Beth-El. Steinfeldt gave lessons and encouraged the study of music throughout his career. He was president of the San Antonio College of Music, which he founded in 1920. He had four children with wife Vivia May Steinfeldt: Cecile, John Jr., Robert and Eric. Cecile and John Jr. were also accomplished musicians and taught for a few years at the San Antonio College of Music. Music scores, correspondence and scrapbooks, which contain clippings and other ephemera. The material, most of which dates from 1900-1954, documents events in the career and personal life of John M. Steinfeldt. The collection includes some of his musical compositions, including published works, drafts, sketches and fragments of his work. Some material also concerns the activities of his wife and children, particularly those of his daughter Cecile.