For sixty years, since the first edition in 1935, Vuelta a Espana was a spring race. The first time the Spanish grand tour started in September happened only in 1995. The race was won by Laurent Jalabert.
This was a much significant change in the calendar, than we might think of it from our present perspective. A grand tour in September has lenghtened the season significantly. And as this cyclingnews article from 2008 shows it, even 13 years later not everybody liked the changes.