Specializing in early and Baroque classical music, Telefunken aka Teldec was a collaboration between Decca and Telefunken.
They created a sublabel in 1958, Das Alte Werk which had a greater focus on early music and historically correct performances using older instruments.

Concentus Musicus Wien conducted by Nikolaus Harnoncourt and the Leonhardt-Consort conducted by Gustav Leonhardt featured prominently on the label.