George Bernard Shaw to the Times of London:
There is a pedant on your staff who spends far too much of his time searching for split infinitives. Every good literary craftsman uses a split infinitive if he thinks the sense demands it. I call for this man’s instant dismissal; it matters not whether he decides to quickly go or to go quickly or quickly to go. Go he must, and at once.
Cited in Patricia T. O’Connor’s Words Fail Me: What Everyone Who Writes Should Know about Writing.
HT: Trevin Wax