What was (is) the purpose of the division line?

[CMHCoachNRef]

There is a line that goes across the court that we call the "division line." As we have discovered in another thread, this line is not used to determine where players must stand for free throws as a result of technical fouls.

What was the original intent of this line?

I am trying to establish a "base line" (not to be confused with the "end line") for a discussion.