Final answer:
The Kingdom of Pontus, led by Mithridates VI, was the last kingdom to fall to Rome, ending its resistance in 63 BCE.
Step-by-step explanation:
The kingdom that was last to succumb to Rome was the Kingdom of Pontus, in the early first century BCE. Mithridates VI led the last great Hellenistic resistance against Roman control, starting in 88 BCE. Despite forming a large anti-Roman coalition and being seen as a liberator from Roman corruption, Mithridates was ultimately defeated and killed in 63 BCE, marking the end of the kingdom's resistance to Roman domination.