It happened when both were created by the Creator.
A monkey and a man are two different species. There is NO EVIDENCE in this case, or any other case, of one species evolving into another. All the Church of Evolution can offer up are wild assumptions, artist paintings, bones carefully arranged to somehow try to make a case, faulty dating methods, etc.
Evolution is just another faith-based religion that has no place in our school system.
OK, so this alleged 'creator' deliberately made us, chimps, gorillas et al subject to scurvy? But not monkeys, or dogs, or platypuses, or any other mammal (except guinea pigs, which have a different mutation).
Why just the great apes? Why the exact same mutation? Is the alleged 'creator' deliberately trying to fool us?