This is my first game. Vanilla, up to date version. I'm Rome. I have Warriors, that are in my territory. I want to upgrade them to Legions. I have the money. I don't see the up arrow with gold in the unit choices that people talk about. Legions don't need Iron, but do I need to have at least one Iron for the upgrade to show up (even though it wouldn't be used)? Or do the Warriors need to be at 100 HP? Those are the only things I can think of. The units do have movement available.