Plutarch Galba 15

[1] Such was the violent end of Nymphidius, and when Galba learned of it, he ordered such of his fellow-conspirators as had not at once taken their own lives to be put to death. Among these was Cingonius, who wrote the speech for Nymphidius, and Mithridates of Pontus. But it was held to be illegal and despotic, even though just, to put to death without a trial men who were not without distinction. For everyone expected a different mode of government, being thoroughly deceived, as is usual, by assurances made in the beginning.

[2] And people took it still more amiss when Petronius Turpilianus, a man of consular dignity who was faithful to Nero, was ordered to take his own life. For in having Macer taken off in Africa at the hands of Trebonius, and, Fonteius in Germany at the hands of Valens, Galba could excuse himself with the fear they inspired as commanders of armed forces. But there was no reason why Turpilianus, a helpless old man and unarmed, should not have a chance to defend himself, if the emperor was really going to observe that moderation in his dealings which he promised.

[3]
  Such, then, was the censure to which these acts exposed Galba. Moreover, when, in his approach to the city, he was distant from it about five-and-twenty furlongs, he fell in with a disorderly and tumultuous crowd of seamen, who beset his way and encompassed him on all sides. These were men whom Nero had formed into a legion and given the title of soldiers.

[4] And now they were there to enforce their just rights as soldiers, and would not suffer the emperor to be seen or heard by those who came to meet him, but with tumultuous shouts demanded standards for their legion and regular quarters. When Galba put off their demand and told them to renew it at another time, they declared that the postponement was merely a way of refusing their demands, and were incensed, and followed along with unremitted shouts. Some actually drew their swords, and then Galba ordered his horsemen to charge upon them. Not a man of them stood his ground, but some were done to death at once in the rout, and others as they fled, nor was it a happy and auspicious omen that Galba should enter the city through so much slaughter and so many dead bodies. But whereas many had before this despised him and looked upon him as a weak old man, now all regarded him with shuddering fear.