Observation #1) Army loaded with only Hidden Nationality Unit (s), they can attack without starting a war, but if you attack them it starts a war. The AI created an army and loaded a hidden nationality unit; hence, the white flag. Their nationality is given away by the a secondary civ colour that tells me it is the Sioux (cyan colour). I was thinking that maybe this colour should always be a neutral colour, black would probably work. They attacked Carthage without starting a war. Then they attacked me without declaring war and did not start a war. When I went to return fire on my turn, which I have been doing during the game already on hidden nationality units that are not loaded in an army, the window popped up saying I would being declaring war, would you like to continue. Adding a hidden nationality unit to an army adds a whole new dimension. You prompted me to set up a test. If you load a single hidden nationality unit into the army and attack, then they attack without starting a war. Add a second hidden nationality unit to the army and the same thing happens. If the second unit added to the army is a non-hidden nationality (nationality declared), then the army declared war at the start of the fight, not in the middle. So there is no starting a war in the middle of a fight. Edit: On further game play, I as a human player built an army with a single unit with hidden nationality and tried to attack an AI city , the game would not allow me to attack (the capture flag is set on the hidden nationality unit), it was like I was trying attack with a worker, except there wasn't even a message saying that this unit could not attack. The game just didn't acknowledge anything, it was like it was an impassible tile. The thing is that the game allows the AI to attack a city with the same army configuration. I also noticed that the army flag was my civ colour while the AI army flag colour would be white. This army has no problem attacking enemy units without starting a war, you just can't attack a city, but they AI is allowed to. Here is an example of an in game test I did as a human trying to attack a city with an Army loaded with Hidden Nationality Unit: 1) I am not at war. 2) I tried to atttack a city with the Army loaded with Hidden Nationality Unit and the game doesn't even give a message telling me that I would be declaring war, it just doesn't let me go to that tile/city. 3) I go to the diplomacy windows and declared war on that civ, then the Army loaded with Hidden Nationality Unit has no problem attacking that city and has no problem occupying that city. The AI doesn't have that problem. The AI can attack a city with the Army loaded with Hidden Nationality Unit and not declare war. I haven't tried to attack a enemy unit in a barricade with the human player's Army loaded with Hidden Nationality Unit, I will update when I do. One more thing, the AI Hidden Nationality in an Army or Hidden Nationality no-Army can attack a human army without declaring war, but the Human can not do the same. Observation #2) I noticed, not with armies, but in a similar vein: If a unit with hidden nationality is in a barricade/fortress and in its territory and you attack, you will be declaring war. The barricade/fortress gives the unit it's nationality, just like the army does. Funny thing is that I can bomb or bombard that unit in the barricade/fortress without starting a war, but if I attack with a ground unit I will be declaring war. Observation #3) I have confirmed for myself (others may have already done so): If a hidden nationality unit (not loaded into an army, just the unit) attacks a Civ's unique unit and the unique unit wins the battle, then the unique unit's Civ goes into a Golden age (if it hadn't already done so). Observation #4) Something else I noticed, my Privateer (naval unit with hidden nationality) with the bombard flag is not checked. There are bombard parameters but bombard is no selected. The AI uses these units and they are going around bombarding: they actually move in, bombard, then move away, one after the other. The human can not bombard. One more set of crossed wires with hidden nationality. Observation #5) Something else I noticed: There was a hidden nationality immobile artilly by itself on what is now my territory (city was razed and it was left behind). I wanted to build a road to that tile but when I told the worker to build a road to that tile it would not go. So I moved a unit to the tile so it was sitting on the tile with the artillary, then it allowed me to give a build road to that tile command. It was sort of like loading units on a boat, if you were not adjacent to the boat you could not load, but in this case, once you have a unit on the tile you can. BTW, Once an AI goes on this tile with an offensive unit, you can't use the goto command to get off the tile you must step off to an adjacent tile and then you can use the goto command from the adjacent tile. Eliminating the civ does not make the hidden nationality immobile units go away. You can found a city on top of one of these units. Once the city is built on this tile the hidden nationality immobile units disappear. Example: Here is a pick showing the units on a tile with the Sea Cannons (the Hidden Nationality Immobile Units), they belong to no one since the Civ has been destroyed. I then moved miltary unit (unit with attack) onto the tile with the Sea Cannon, then I moved my workers onto the tile to clean up the ruins and build irrigation and roads. The Persians then decided to move there military units onto the tile and now we all occupy the tile together. For a test, I then abandoned the near by city so I could build a city with the settler and the Sea Cannons went away and I assume that the Persian units went back to their capital. The new city happened to get the same name as the city I abadoned. What gets odd is I can't add any more offensive units to the tile after the AI has moved onto the tile, where the AI seems to have no problem adding more units, so you better get your settler on the tile with your offensive units before the AI does otherwise you will be blocked from building the city. Observation #6) One thing I have noticed with Armies that is notable. 1) I loaded A Hidden Nationality King Unit into an army, the army remained hidden nationality. Can attack without starting a war. 2) I loaded a second Hidden Nationality King Unit that was the same unit type as the first into the same army and the army remained hidden nationality. Can attck without starting a war. 3) If I loaded two Hidden Nationality King Units that are different unit types into the army, the army is no longer hidden nationality and will start a war if it attacks a rivel unit.