SUETONIUS, Life of Tiberius
[VII] Virili toga sumpta adulescentiam omnem spatiumque insequentis aetatis usque ad principatus initia per haec fere transegit. Munus gladiatorium in memoriam patris et alterum in aui Drusi dedit, diuersis temporibus ac locis, primum in foro, secundum in amphitheatro, rudiaris quoquequibusdam reuocatis auctoramento centenum milium; dedit et ludos, sed absens: cuncta magnifice, inpensa matris ac uitrici. Agrippinam, Marco Agrippa genitam, neptem Caecili Attici equitis R., ad quem sunt Ciceronis epistulae, duxit uxorem; sublatoque ex ea filio Druso, quanquam bene conuenientem rursusque grauidam dimittere ac Iuliam Augusti filiam confestim coactus est ducere non sine magno angore animi, cum et Agrippinae consuetudine teneretur et Iuliae mores improbaret, ut quam sensisset sui quoque sub priore marito appetentem, quod sane etiam uulgo existimabatur. Sed Agrippinam et abegisse post diuortium doluit et semel omnino ex occursu uisam adeo contentis et [t]umentibus oculis prosecutus est, ut custoditum sit ne umquam in conspectum ei posthac ueniret. cum Iulia primo concorditer et amore mutuo uixit, mox dissedit et aliquanto grauius, ut etiam perpetuo secubaret, intercepto communis fili pignore, qui Aquileiae natus infans extinctus est. Drusum fratrem in Germania amisit, cuius corpus pedibus toto itinere praegrediens Romam usque peruexit.
VII. After assuming the manly habit, he spent his youth, and the rest of his life until he succeeded to the government, in the following manner: he gave the people an entertainment of gladiators, in memory of his father, and another for his grandfather Drusus, at different times and in different places: the first in the forum, the second in the amphitheater; some gladiators who had been honorably discharged, being induced to engage again, by a reward of a hundred thousand sesterces. He likewise exhibited public sports, at which he was not present himself. All these he performed with great magnificence, at the expense of his mother and father-in-law, He married Agrippina, the daughter of Marcus Agrippa, and granddaughter of Caecilius Atticus, a Roman knight, the same person to whom Cicero has addressed so many epistles. After having by her his son Drusus, he was obliged to part with her,' though she retained his affection, and was again pregnant, to make way for marrying Augustus' daughter Julia. But this he did with extreme reluctance; for, besides having the warmest attachment to Agrippina, he was disgusted with the conduct of Julia, who had made indecent advances to him during the lifetime of her former husband and that she was a woman of loose character, was the general opinion. At divorcing Agrippina he felt the deepest regret; and upon meeting her afterwards, he looked after her with eyes so passionately expressive of affection, that care was taken she should never again come into his sight. At first, however he lived quietly and happily with Julia; but a rupture soon ensued, which became so violent that after the loss of their son, the pledge of their union, who was born at Aquileia and died in infancy, he never would sleep with her more. He lost his brother Drusus in Germany, and brought his body to Rome, traveling all the way on foot before it.