The hasty summons to the East which interrupted Marcus’ northern campaign was due to the revolt of one of his best generals, Avidius Cassius. Cassius until now had been loyal to the Emperor and had served him well in the war against the Parthians. In that war the worthless debauchee Lucius Verus, Marcus’ colleague, had been nominally in command, but really confined his campaigns to the voluptuous groves of Daphne, while Cassius bore the brunt of the fight. Further, Cassius had by iron discipline restored the efficiency of the Eastern legions. At first, like all reformers, he was cordially hated; this hatred found expression in mutiny; but, on this being suppressed, gave place to respect and even to popularity. It were well for Cassius had he confined his zeal for reform to the army; but he wished to reform the Emperor and the court also. His murmurings became public property, and Lucius Verus wrote to Marcus warning him against him: “I would you had him closely watched. For he is a general disliker of us and of our doings; he is gathering together an enormous treasure, and he makes an open jest of our literary pursuits. You, for instance, he calls a philosophising old woman, and me a dissolute buffoon and a scamp. Consider what you would have done. For my part I bear the fellow no ill-will; but again I say take care that he does not do mischief to you and to your children.” The answer of Marcus gives a most searching insight into his character. Steeped in the most obstinately logical fatalism, it is yet generous and noble and “breathes the very soul of careless magnanimity reposing upon conscious innocence”:-- “I have read your letter, and I will confess to you I think it more scrupulously timid than becomes an Emperor, and timid in a way unsuitable to the spirit of our times. Consider this--if the Empire is destined to Cassius by the decrees of Providence, in that case it will not be in our power to put him to death, however much we may desire to do so. You know your great-grandfather’s saying, ‘No prince ever killed his own heir’; no man, that is, ever yet prevailed against one whom Providence had marked out as his successor. On the other hand, if Providence opposes him, then, without any cruelty on our part, he will fall spontaneously into some snare prepared for him by destiny.... For Cassius, then, let him keep his present temper and inclinations, and the more so, being (as he is) a good general, austere in discipline, brave, and one whom the State cannot afford to lose. For as to what you insinuate, that I ought to provide for my children’s interests, by putting this man judiciously out of the way, very frankly I say to you, ‘Perish, my children, if Avidius shall deserve more attachment than they, and if it shall prove salutary to the State that Cassius should triumph rather than that the children of Marcus should survive.’”