In 1890 Thiel founded the Kirchliche Singschule, a choir consisting of members - mainly teachers - of all Catholic parishes in Berlin. After his studies he was appointed "etatmäßiger Hilfslehrer" for Gregorian chant at the institute in 1891. Among other things, he devoted himself intensively to the Gregorian chant, because in his opinion, of all music genre, this was best suited to the liturgy. In 1892 he started as a church musician in the parish church St. Sebastian, Berlin in Gesundbrunnen, where he already found a church choir."Carl Thiel" in Algemene Muziek-Encyclopedie, Antwerp, Zuid-Nederlandse Uitgeverij (1963) In 1898, the Kirchliche Singschule was renamed to Verein für klassische Kirchenmusik, which consisted of the St. Sebastian choir. At the turn of the century Thiel lived in Charlottenburg.
