We always know that the eternal city of Rome was not built in a day but what if it survived up to the present day? Many scholars have attributed the rise of Christianity to the eventual downfall of the empire from the fall of Rome in 476 AD to the capture of its eastern remnants of Constantinople in 1453.
In a scenario conceptualized by Robert Silverberg in the 2003 novel "Roma Eterna," it seems that the Roman Empire would have expanded unopposed without the influence of the Christian religion. The point of divergence happened when the Israelite exodus from Egypt failed and the pharaoh Ramses II managed to prevent Moses from 'liberating' his own people. It is said that Moses and many of the Israelites drowned at the Red Sea while pursuing Egyptian army killed those left behind. Meanwhile, the remnants led by Aaron were brought back to slavery in Egypt, a traumatic event recorded for posterity in the Book of Aaron, an alternate version of the Bible. Although the Hebrews were freed from bondage later on, they have remained a distinct religious-ethnic minority in Egypt where continued to practice a monotheistic religion.
Although many major events remained almost similar to our historical Roman Empire, it never became Christianized as the religion never came to be. There was rise and fall of empires and although it was divided into the Western and Eastern empire, both have survived barbarian invasions and kept Roman rule intact throughout the imperial dominions.
Over a period of about 1500 years from 1282 ab urbe condita (AD 529) to 2723 AUC (AD 1970), Roman history covered significant events from the 'cold war' between the Western and Eastern Empires to dominate the other to the violent creation of the Second Roman Republic in about 2603 AUC (AD 1850). Other notable events include the first Roman circumnavigation of the world and the unsuccessful attempts to conquer Nova Roma (North America).
Eventually, the surviving Hebrews attempted another exodus to space 4000 years after Moses' failed mission to liberate his people!