To be a little more specific - the GSD was developed from 3 different regional types of dogs. Horand, I believe, represented the Thuringian regional type. The other types that were included in early development of the breed were the Wurttemberg and Swabian dogs. None were what we would call 'breeds', but regional types that were bred for purposes suiting their environment and the work they were required to do.
Max von Stephanitz and others combined these three types, through line breeding and inbreeding, to establish the breed we know today.
Omen v Wolfstraum
Jasmine Katie v Doolanshaus