It was at one point the phone company arm of deutsche post (the German post office) of which both Telekom and DHL were spun out to be privatised. Both kind of natural monoplies turned private companies which were able to fund large expansions into foreign markets essentially on the backs of German taxpayers and later users of their respective services in their home market.

Holy am I glad that I live in a place where there is a non Telekom ISP well established. Telekom in Germany is a service and troubleshooting hell like you wouldn’t belive if you haven’t had the pleasure of dealing with them.