What was the first Audi?

If you wish to get into detail the first "Audi" was back in 1901 but this was under the name Horch. The first one a 4.4hp Engine!!

As for the modern day Audi, You cannot really say what was the first as like today it was just a base chassis that had a number of different body and engine options. The base was called the F103, this was used to make the 72 (Also called "Audi") from 1965 and also went on to make the Audi 80 an 90 (and more). This design was used in till 1972 when they changed to a new design called the B1. :)