In what year was the Audi brand founded?

In what year was the Audi brand founded? The Audi brand was founded in 1909.

Engineer August Horch established a new automobile company in Zwickau on 16 July 1909 after leaving his earlier company, which still held the Horch name. Because he could not continue using his surname as a trademark, a legal dispute led to the Latin-based name Audi, meaning “listen,” equivalent to “horch” in German.

The 1909 date refers specifically to the founding of Audi itself. Audi's broader corporate history is more complicated: Horch, DKW, Wanderer and Audi became parts of Auto Union in 1932, represented by the four-ring emblem. Volkswagen acquired Auto Union in the 1960s, and the Audi name was revived for new vehicles.

Some references instead mention 1899, the year Horch founded his first company, or 1932, the year Auto Union was formed. Neither date is the founding year of the Audi brand as asked here, making 1909 the canonical quiz answer.