Why do German football clubs have a number in their name?

According to this article on the the Bundesliga's website:

Germans are traditionally sticklers for accuracy and they're no different when it comes to football. As a general rule of thumb, if you see a '1.' in front of your team's name that's because they want you to know they were the first such club to be founded in their city. Similarly, any other numbers that feature (usually at the end) demonstrate the club's pride in their historical roots by flaunting the year they came into existence.