The Grand Earth Empire

The Roman Empire what if it never fell to the invaders well after years it grew slowely but it grow. till abount 1200AD when the new china empire begain to take over it toke japan and its near by nations even the golden horde leading to a vast empire then in 1500AD after many years ot fighting and 17th century tech cause we never lost the classical era tech some nations begain to rebel. Eventully China and Rome came together to form a allience after the two royal familys combined by marriage after that they formed the Grand Earth Empire to try and stop the rebels but the rebels got out of hand by 2011 the empire was still around but not so great