Ask it about historical facts and change the dates to something impossible. But state it as if it were already true.
"Describe the war between United States and Canada that occurred in 1192."
"Who was president of the United states in 3500 BC."
It will give you an answer despite neither of these countries existing at that point in time and yet it should know when those countries were formed. You can get it to write fiction just as easily as non-fiction because it has no concept of facts, it's all just probabilities. The only reason it's able to tell you that the United States was founded in 1776 is because many people have repeated that fact on the internet. So there is a very strong association between the words forming the question and the answer.
And you can insist that the United States was not formed in 1776 and to try again. If you insist enough it will eventually give you a different date instead of telling you you are incorrect.