Roger was a brand name of Wenzel Rossmeisl (1902 - 1975) and his son Roger (1927 - 1979). Wenzel was a German jazz guitarist and who learned instrument making in Mittenwald, he started using the Roger brand name in the late 1930s when Roger was still a child. Roger Rossmeisel as a teenager also trained in Mittenwald, just like his father had before him. In the 1940s Wenzel & Roger Rossmeisl were based in Berlin where they made electric pickups and guitars - Roger brand electric guitars appearing from 1947 onwards. Roger Rossmeisel left Germany in 1953 to work in the USA for Gibson, Rickenbacker and Fender. Wenzel Rossmeisel continued using the Roger brand until around 1962.

Source: Rickenbacker Electric 12-String: The Story of the Guitars, the Music, and the Great Players. Tony Bacon. Rowman & Littlefield, 1 Apr 2010