Caelius will always repay fresh study; he was amusing and interesting to his contemporaries, and so he will be for ever to us.

He is a veritable Proteus--you never know what shape he will take next; Omnia transformat sese in miracula rerum---- we can trace no less than six such transformations in the story of his life.

And this instability, let us note at once, was not the restlessness of a jaded _roue_, but the coruscation of a clever mind wholly without principle, intensely interested in his _monde_, in the life in which he moved, with all its enjoyment and excitement.
Caelius' father brought his son to Cicero, as soon as he had taken his toga virilis, to study law and oratory, and Cicero was evidently attracted by the bright and lively boy; he never deserted him, and the last letter of Caelius to his old preceptor was written only just before his own sad end.

But Cicero was not the man to keep an unstable character out of mischief; he loved young men, especially clever ones, and was apt to take an optimistic view of them, as he did of his own son and nephew.

Caelius, always attracted by novelty, left Cicero and attached himself to Catiline; and for this vagary, as well as for his own want of success in controlling his pupil, Cicero rather awkwardly and amusingly apologises in the early chapters of his speech in his defence.