hmmm.. ok here is my alternative history timeline-
AD 300- Roman Senete remove the Emperors from power, taking it for themselves, The Seneate reform the Roman Empire and mend the screwing up the Emperors did. The Empire is never divided.
AD 300- 400- A series of wars against Barbarians, the Roman's survive, and go on to conquer mainland Europe.
400-800- Wealth and prosperity increase, Christianity never becomes the official state religion, but competes against a number of pagan religions.
1000 AD- Vikings discover America, the senate hear of this and interest, commission the exploration and settlement of America.
1200-American and Canadian East Coast colinised by the Roman Empire- where New York lies today, there is the city of Nova-Roma. There are wars against the Indian Tribes.
1200-1400- Roman Empire gradually becomes a federation as power is handed back down to states- the federated states share the same language (Latin) currancy, culture and roughly similar laws. This prevents Civil Wars in Europe or America.
1500-1600- Exploration and colinisaton of other lands, industrial revolution occurs early due to more progression of technology.
1700-1900- The Jacques brothers, two Gauls, make mans first sucessful flight in 1710. later, aircraft, computers, advanced medicines and treatments are developed and become common place. The Roman State of America lands on the moon in 1840. Mars by 1910. Nuclear Weapons invented in 1822 by German scientists.
1900-2000- Genetic revolution, people stay young, age slowly and live up to around 200. Robots and androids mass produced, Nuclear Fusion developed in 1922, Mars and Moon colonies founded by 1945, Asteroid mining kicks off in the 1960's, and by the year 2000 mankind is heading off towards the distant stars.