Successful Beetle model run raised a considerable amount of capital for VW. In search for an investment opportunities VW acquired a controlling stake in Auto Union… with its barely breathing sub brands Audi, ,DKW, Horch and Wanderer.
Liudwig Kraus was in charge of Audi’s 100 prototype. It was developed on VW C1 platform, almost secretly.
Production ready Audi C1 was presented to Volkswagen’s board of directors. They where so impressed and confirmed Audi’s production plan in its entirety.
This project saved Audi from extinction.
First spacious Audi 100 sedan equipped with 100 horsepower engines rolled off the production line in 1968. Engine’s 100 horsepower reading was the main reason why this model was named the Audi 100.

The engine range featured a 1.8- and 1.9-liter units. Most of them were feed via a carburetor, but in 1975 there was a fuel-injection system added to the lineup. The standard transmission was a 4-speed manual, with a 3-speed automatic joining the range later on
The car launched as a four-door saloon but quickly gained other body styles. There was a two-door saloon and even a fastback coupe model called Audi 100 Coupe S. To me latter seems incredibly similar to the Aston Martin DBS. Let me know your opinion in the comments.
The Audi 100 C1 was a huge success. over 800,000 units were sold by the year 1976, when it was replaced by Audi C2.