When Tribune Company bought the Cubs in 1982, they re-numbered all the seats in Wrigley Field.
This was a good thing, because here was the seating/numbering chart as of 1978 (click here for a larger version):
Well, that was a mess. (Note, the numbers in each section are the number of seats in that section.) And remember, as Jack Brickhouse used to remind us on WGN, there were “22,000 unreserved grandstand and bleacher tickets” available for every game. With Tribune’s ownership, this changed. The Cubs now sold every seat in advance, and thus (except for the bleachers, which remained and still are unreserved), they would need a more accurate seating-number arrangement.