!! The American civilization in Thrones and Patriots are actually [[http://en.wikipedia.org/wiki/Nephite Nephites]] and the game creators are secretly Mormon.

That would explain them existing during the ancient age when doing a Conquer the World campaign.

!!Rise of Legends takes place AfterTheEnd.

Our future weapons drastically altered the very laws of physics. This did not end well for everybody.

!! The American government in the Thrones and Patriots Cold War campaign are controlled by radical extremist.

In the many playthoughs that this troper had playing the Cold War Campaign as the Soviets, if part of the US mainland is in my control by the time that Defcon 1 was reached, the Americans will NUKE the parts of their own country that are under Soviet control. In fact, they will give it even higher priority then major cities in Russia. This doesn't happened if the situation is reversed (The Russians will never nuke their own country unless they ran out of places to nuke). My only explanation is that the US government in the campaign is under the control of an axe crazy extremist.
** Or, at least, that the USA ends up falling to radical extremists 'off-screen' if things go so bad that the Soviet Union is in a position to invade the US proper.

!! Romans in the later eras are Italians.
* Well duh!

!! In Thones and Patriots, the Lakota's unique ranged calvary

For those of you who don't know, the Lakota's ranged calvary always has guns that do not fit the current age in regards to all the other nations (i.e. they get flintlock musket wielding horsemen in an age where everyone else has the bulk of their army using matchlocks muskets and repeating rifles when everyone else is using flintlocks). There is actually a good reason for that: the infantry and ranged calvary are using "standard" equipment. To explain, everyone else's armies are using weapons that the army considers "standard issue", no matter if there might be better weapons out there. They simply haven't got the time, the money or maybe the experience to outfit their whole army with the better weapons until the next age.
The Lakota on the other hand, don't us a "standard army" in a traditional sense, they use what ever they can buy from trade and that sometimes means they get their hands on weapons not currently used by other armies in the same age. Even history has examples where native american tribes on the Great Plains used repeating rifles they got from trading against the US Calvary, which at the time used single shot carbines.