Basically the taxes were raised a ton due to government spending which caused riots. I'm not sure what was considered the official start though, sorry!<span />

⚘The Roman Republic (Latin: Rēs pūblica Rōmāna [ˈreːs ˈpuːblɪka roːˈmaːna]) was the era of classical Roman civilization, led by the Roman people, beginning with the overthrow of the Roman Kingdom, traditionally dated to 509 BC, and ending in 27 BC with the establishment of the Roman Empire. During this period, Rome's control expanded from the city's immediate surroundings to hegemony over the entire Mediterranean world

It is never okay to dominate another country.
Explanation:
No one likes being dominated, if a person were to be heald against a wall by another person to be proven as week it could lead to conflict, so if one country were to dominate another it could lead to losing and allie or if not losing one then gaining one.