If the older noble families were apathetic and idle, there were plenty of young men, rising most often from the class below, whose minds were intensely active—­active in the pursuit of pleasure, but pleasure in the comparatively harmless form of amusement and excitement.  One of these, the son of a banker at Puteoli, Marcus Caelius Rufus, stands out as a living portrait in his own letters to Cicero, of which no fewer than seventeen are preserved.[192] Of his early years too we know a good deal, told us in the speech in defence of him spoken by Cicero in the year 56; and these combined sources of information make him the most interesting figure in the life of his age.  M. Boissier has written a delightful essay on him in his Ciceron et ses amis, and Professor Tyrrell has done the like in the introduction to the fourth volume of his edition of Cicero’s letters; but they have treated him less as a type of the youth of his day than as the friend and pupil of Cicero.  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.  Wild oats must be sown, he says; when a youth has given full fling to his propensities to vice, they will leave him, and he may become a useful citizen,—­a dangerous view of a preceptor’s duty, which reminds us of the treatment, of the boy Nero by his philosopher guardian long afterwards.[193]