Telefunken was one of those exotic sounding (to my ears) labels when I started buying records in the mid seventies. German only notes, artists that were generally unknown in the states, high import prices. Later I learned that their history stretched back into the 1930s and possibly earlier, and that they were responsible for many famous records made in Germany before and during WWII.
They renamed themselves as Teldec in the eighties and then folded some time after that. I never knew that they were part of the Decca stable but given the label consolidation in the Classical industry it doesn’t surprise me.
They had a spin off label dedicated to Early Music named Das Alte Works that was very important in launching the Historically Informed Performance Practice (HIPP) movement