Cicero considered Mithradates the greatest king since Alexander. He orchestrated the "Asiatic Vespers," a coordinated killing of 80,000 Romans and their allies, and fought three major wars against Rome’s top generals for decades.
Not all who fought Rome came from without; many of the fiercest struggles originated within the empire's borders.
Masada: A heroic last stand against Rome - Princeton University Press
For over two centuries, the Jewish people launched large-scale revolts against Roman rule. These conflicts, driven by a desire for political and religious independence, culminated in the destruction of the Second Temple in 70 CE and the legendary "last stand" at Masada , where nearly 1,000 people reportedly chose death over enslavement.
The ultimate collapse of the Western Roman Empire was the result of sustained pressure from Germanic and tribal groups that were often pushed into Roman territory by climate change and external threats like the Huns.
In the East, the Parthians dealt Rome one of its greatest military disasters at the Battle of Carrhae in 53 BCE. Their superior cavalry and mounted archers annihilated the legions of Marcus Licinius Crassus , stalling Roman expansion into Persia for centuries. Internal Resistance: The Struggle for Liberty