The answer is : <span>Conquest of the Roman empire followed by Germanic invasions</span>
I'm pretty sure its the first one
The raids were the first in what would become a three-year program of sustained bombing targeting sites north of the seventeenth parallel.The troops were the first in what would become a three-year escalation of U.S. military personnel fighting a counterinsurgency below the seventeenth parallel. Together, they Americanized a war the Vietnamese had been fighting for a generation
( This isn’t my answer all credit to taylormccord!!!! just wanted to help this person)