The asteroids sharing Jupiter’s orbit around the sun fall into two large groups. When working to correctly calculate their orbits, astronomer Johann Palisa started the convention to call one group of asteroids “Trojan” and the other “Greek.” And asteroids in each group are given names from their respective groups – Achilles for a Greek asteroid, for instance.
However, the asteroids 617 Patroclus and 624 Hektor were named before the Greek/Trojan rule was suggested, resulting in a Greek spy in the Trojan camp and a Trojan spy in the Greek camp.
