Is It Possible to Train a Military Unit Up for a Year and Send It Back?

Could we create a city state phalanx and send it back in time to take on ancient greek times? Do you think our, even military unit would stand there when the spears start jabbing in each other's faces and not run away? How long does it take for the culture to rebuild the ability to do a skill that has not been necessary for a very long time. It seems to be both particularly feared, as one might expect, but also particularly abhorrent to the people who have to do the scewring.