Time Traveler

I run East into the farmer's fields that surround this battle site. No one pursues me. I have some breathing room, so I stop to think what the message might have meant. I remember that the Caesar cipher is a simple substitution cipher. To encipher a message, each letter is substituted with the letter three places farther in the alphabet. A becomes D, and so forth. So to decipher, I just take each letter back three places in the alphabet. PHULGLDQXV becomes MERIDIANUS. That means noon or South, since the sun is always to the south at noon, at least in the northern hemisphere. So if the army was south of the skirmish line, it must be southwest of where I am now.