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Death

After Pompey defeated him in Pontus, Mithridates VI fled to the lands north of the Black Sea in the winter of 66 BC in the hope that he could raise a new army and carry on the war through invading Italy by way of the Danube. His preparations proved to be too harsh on the local nobles and populace, and they rebelled against his rule. He reportedly attempted suicide by poison, which failed because of his immunity to the substance. According to Appian's Roman History, he then requested his Gallic bodyguard and friend, Bituitus, to kill him by the sword:

Mithridates then took out some poison that he always carried next to his sword, and mixed it. There two of his daughters, who were still girls growing up together, named Mithridates and Nysa, who had been betrothed to the kings of Egypt and of Cyprus, asked him to let them have some of the poison first, and insisted strenuously and prevented him from drinking it until they had taken some and swallowed it. The drug took effect on them at once; but upon Mithridates, although he walked around rapidly to hasten its action, it had no effect, because he had accustomed himself to other drugs by continually trying them as a means of protection against poisoners. These are still called the Mithridatic drugs.Seeing a certain Bituitus there, an officer of the Gauls, he said to him, "I have profited much from your right arm against my enemies. I shall profit from it most of all if you will kill me, and save from the danger of being led in a Roman triumph one who has been an autocrat so many years, and the ruler of so great a kingdom, but who is now unable to die by poison because, like a fool, he has fortified himself against the poison of others. Although I have kept watch and ward against all the poisons that one takes with his food, I have not provided against that domestic poison, always the most dangerous to kings, the treachery of army, children, and friends." Bituitus, thus appealed to, rendered the king the service that he desired.

Cassius Dio 's Roman History records a different account:

Mithridates had tried to make away with himself, and after first removing his wives and remaining children by poison, he had swallowed all that was left; yet neither by that means nor by the sword was he able to perish by his own hands. For the poison, although deadly, did not prevail over him, since he had inured his constitution to it, taking precautionary antidotes in large doses every day; and the force of the sword blow was lessened on account of the weakness of his hand, caused by his age and present misfortunes, and as a result of taking the poison, whatever it was. When, therefore, he failed to take his life through his own efforts and seemed to linger beyond the proper time, those whom he had sent against his son fell upon him and hastened his end with their swords and spears. Thus Mithridates, who had experienced the most varied and remarkable fortune, had not even an ordinary end to his life. For he desired to die, albeit unwillingly, and though eager to kill himself was unable to do so; but partly by poison and partly by the sword he was at once self-slain and murdered by his foes.

At the behest of Pompey, Mithridates' body was later buried alongside his ancestors (in either Sinope or Amaseia). Mount Mithridat in the central Kerch and the town of Yevpatoria in Crimea commemorate his name.