And just how did you arrive at that remarkable conclusion, Mr. Mayor? - Isaac Asimov

In part because of a man named Elijah Baley, an Earthman."
Pelorat put in excitedly, "He is the culture-hero I mentioned some time ago, Golan."
"A culture-hero, sir?"
"What Dr. Pelorat means," said Trevize, "is that he is a person to whom much was attributed, and who may have been an amalgamation of many men in actual history, or who may be an invented person altogether."
Daneel considered for a moment, and then said, quite calmly, "That is not so, sirs. Elijah Baley was a real man and he was one man. I do not know what your legends say of him, but in actual history, the Galaxy might never have been settled without him.

I accept only what I am forced to accept by reasonably reliable evidence, and keep that acceptance tentative pending the arrival of further evidence.

Had Hannibal had a government behind him that knew how to exploit victories – had he been born a Roman, for instance – he might have conquered the world.