The Porsche 911 was originally designated the Porsche 901 before a legal dispute led to the name 911.
Porsche unveiled the 901 at the 1963 Frankfurt Motor Show as the successor to the four-cylinder 356. It used a rear-mounted, air-cooled, 2.0-litre flat-six engine and was designed by Ferdinand Alexander Porsche and his team.
When Porsche displayed the car at the Paris Motor Show in October 1964, Peugeot objected to the 901 designation. Peugeot claimed rights in France to three-digit vehicle names with a zero in the middle. Porsche changed the central digit from 0 to 1, creating 911, while retaining 901-based internal type and part numbers.
The 901 name is therefore not a different Porsche model in the usual sense: it is the original designation of the car that became the 911. The 930, 914 and 912 were later Porsche model or type designations, not the original name involved in this dispute.