Answer:
One of the most important factors that led to the establishment of one-man rule in the Roman Republic was the increasing threat of external invasion and internal conflict.
Step-by-step explanation:
As the Roman Republic grew in power and influence, it faced a number of challenges from neighboring states and foreign powers, as well as from internal factions and rivalries. In order to effectively defend the republic and maintain its unity, many Romans believed that it was necessary to have a strong, centralized government with a single leader who could make quick and decisive decisions. This led to the rise of powerful military leaders, such as Julius Caesar, who were able to consolidate their power and establish one-man rule over the Roman Republic.