User blog comment:Wagnike2/Assasin's Creed Fantasy Setting/@comment-5724419-20121110043204

Time period – 1268 Japan

Historical Events - In 1268, an external threat appeared. Kublai Khan, the Mongol ruler of Yuan China, demanded tribute from Japan. Kyoto refused. The Mongols invaded in 1274 with 600 ships, but a typhoon destroyed their armada. A second invasion fleet in 1281 met the same fate.

Historical Actors – Kublai Khan, also the Minamoto and Taira samurai clans

Reasoning – Samurai, Mongols, possibly Ninjas… need I say more? Ok

End of the Heian Era / Rise of Samurai Rule:

The weak imperial line received a fatal blow to its power in 1156, when Emperor Toba died without a clear successor. His sons, Sutoku and Go-Shirakawa, fought for control in a civil war called the Hogen. During this civil war, the Minamoto and Taira samurai clans rose to prominence. They fought one another in the Heiji Rebellion of 1160. After their victory, the Taira established the first samurai-led government, or shogunate, with the emperor as a figurehead.

The defeated Minamoto were banished from the capital at Kyoto.

Kamakura Period:

The two clans fought once more in the Genpei War (1180-1185), which ended in victory for the Minamoto.

(History of the Samurai By Kallie Szczepanski, About.com Guide)