267 BCE -- A series of battles between Rome and King Pyrrhus of Epirus. As the Greeks came into contact with Rome, resulting from Roman expansion across the Italian Peninsula, they increasingly experienced conflict. The Greeks, who relied heavily on mercenaries, bought the aid of King Pyrrhus of Epirus to help in staving off the Romans. King Pyrrhus was able to defeat the Romans in two subsequent battles, where he raised armies of 20,000 or more and crossed the Adriatic Sea with them. Though King Pyrrhus was considered to have won the battles, the victories were thought to have cost more than they gained. King Pyrrhus even remarked that winning one more battle would ruin him, hence the phrase Pyrrhic victory. His words nearly rang true, when Rome decisively defeated King Pyrrhus, 267 BCE. This allowed the Romans to expand into Southern Italy and gain control over the Greek city states.