Under Hadrian he was _magister epistularum_, but was dismissed from office in A.D. 121. Spartianus, _Hadr._ 11, 3, 'Septicio Claro praefecto praetorio et Suetonio Tranquillo epistularum magistro multisque aliis, quod apud Sabinam uxorem in usu eius familiarius se tunc egerant quam reverentia domus aulicae postulabat, successores dedit.' The remainder of his life appears to have been devoted to literature.
1. _De Vita Caesarum_, in eight Books (Books i.-vi. Iulius-Nero; vii. Galba, Otho, and Vitellius; viii. Vespasian, Titus, and Domitian). It was published A.D. 119-21, as it was dedicated (according to Joannes Lydus) to C. Septicius Clarus, praetorian prefect, who held office during those years. The preface and the beginning of the life of Iulius are wanting. Suetonius is a conscientious and accurate writer (cf. his discussion of Caligula's birthplace, _Calig._ 8), and he makes use of good sources, e.g. the _Monumentum Ancyranum_, _Acta populi_, _Acta senatus_, autograph documents of the emperors (_Aug._ 87, _Nero_ 52); but there is in his work an almost entire absence of dates, and the personal element is, from the point of view of history, unduly prominent.
2. _De Viris Illustribus_, including poets, orators (beginning with Cicero), historians (from Sallust onwards), philosophers, grammarians, and rhetoricians. The greater part of the section _De grammaticis et rhetoribus_ is extant, as well as lives of Terence, Horace, and Lucan from the section _de poetis_, and of Pliny the elder from the section _de historicis_. Extracts from the rest of the work are preserved by Jerome. In each section there was (1) a list of the authors discussed, (2) a general survey of their branch of literature, (3) brief notices of the authors in chronological order. The publication took place, according to Roth, 106-113 A.D.
3. Minor works, now lost (mentioned by Suidas), on Greek games, Roman games, the Roman year, on critical marks, on Cicero's _Republic_, on dress, on imprecations (περὶ δυσφήμων λέξεων ἤτοι βλασφημιῶν καὶ πόθεν ἑκάστη), on Roman laws and customs. Some of these were probably only sections of the _Prata_, a miscellany in ten Books, which also treated of natural science and philology. The books on Greek games and on imprecations were almost certainly composed in Greek.