Those who control time control the world
Time.
Currently we are all aware of the notion that control of information is control of the world.
What about control of time? If you can move in time all truth is yours. You can manipulate it, you can change it, you can make the world yours. Do you think if this kind of travel were possible those that had it would tell you?
So you want the Egyptians to have invented the wheel. Go back in time and plant a wheel there. Inventors to come from somewhere, then you just go and tell them how to do something.
Of course, by definition, if it were possible to control time, it would already be controlled, which would mean we are all living in a construct already.
How can you be certain it isn't? How do you know this is not possible? How can you be sure. You can't can you?
