I have a good story for this.
After I purchased Civ 5, I started a game as the Japanese and I got to work. Starting placement was good, and i pretty much had a continent to myself, sharing my space with 2 city states. After several turns of growth, establishing cities and exploration, I finally found a second continent to the east with 3 Civ's on it, India, Germany, and the Songhai. I establish a foothold city close to Germany (i think i developed a bias against them due to there aggressiveness in a Civ4 game i played previously). This does not make them happy, but as i'm considerably more powerful, they only make passive-aggressive taunts.
Several turns later, I find the Native Americans, America, and England. I also find the Mongols. By this time, i think i was harassing allied city states of Germany, and they were getting angry with me. I'm getting annoyed, and i'm itching to see how powerful I've become. Suddenly, Askia of the Songhai decides he wants to declare war on Germany, and asks me if i wish to join him as a war buddy.
I jumped at the chance, and began mobilizing for war. by the time I got to the continent with my armies, Askia had taken 3 German cities. I charge into the battle and take 1 German city. The following turn, Askia Signs a Cease Fire with Germany, and then decides he's going to denounce me! In fact, everyone denounces me in 2 turns!
needless to say, I wasn't happy. I took Germany's next request to sign a peace treaty, and went to work on Askia. I took the 3 cities he took from Germany, and gave them back to their original owner. Then i conquered city after city until Askia had 1 city left on the southernmost tip of a peninsula. I blockaded him there, and left him to waste away.
a few turns later, he tried to expand, so I eliminated him.
