The time limit ran out? How were your men not able to get into the battle before the time limit ran out, it's like an hour long!
Or do you mean that they took the square?
Either way, that sucks. Depending on what was in the army, I'd reload. You might want to start making it a habit to quicksave at the end of or beginning of your turns, so in the event that something like this happens, you can go back and do something differently. Quicksave is Ctrl+S, and quickload is Ctrl+L