What was the main reason that early settlers gradually spread across the americas?

The main reason why early settlers gradually spread across the America because of the attacks from the terrorist in which motivate and ushered them to gradually spread as they look for a place where they could stay and a place that would be beneficial for them in terms of having food and shelter that they need.

it took two men to wrestle rome back from chaos and turn a republic into an empire. in the first century bc, rome was a republic. power lay in the hands of the senate, elected by roman citizens. but the senators were fighting for power between themselves.