Once again about medieval things.
I just realized Genghis Khan/Temujin would be also consider medieval general
I played once a Koei' game Genghis Khan http://koei.wikia.com/wiki/Genghis_Khan_(series)"The game takes the player inside the virtual life of either Genghis Khan or one of his archrivals. The player must arrange marriages, father children, appoint family members to governmental positions, and fight in order to conquer the Old World. Armies must be drafted and soldiers must be trained if the player is to rule the lands from England to Japan."
It was very entertaining and satisfying alone - without even the second part of conquering the whole world.
There were two ways to play. In the first [Mongol Conquest, 1175 AD], player assumed control of Lord Temujin and tried to unite Mongol tribes still keeping stable economy. The second was World Conquest [1206 AD], where the goal was to conquer every opposing country: Kamakura Shogunate, Khorezm Empire, Ghore Sultanate, Angevin Kingdom, Capetian Kingdom, Koryo Kingdom.
Even a few independent campaigns/scenarios gives much fun. You can choose from many: Western Xia Dynasty, Jin dynasty, Qara Khitai, Khwarazmian Empire, etc. My spellchecker does not recognize these names though
Lot's of work but also lot's of fun.