Origin and early career. L. Catilius Severus came from the eastern provinces — variously reconstructed as Apamea in Bithynia or as Antioch in Pisidia (the exact localisation remains a matter of dispute in the prosopographical literature; see Birley 2000 and PIR² C 558). The full polyonymous name — L. Catilius Severus Iulianus Claudius Reginus — reflects several generations of family adoptions and inheritances. This is the first generation in the family to reach the Roman consulate.

Career. Military tribune, quaestor, legate, proconsul of Asia Minor (probably). Suffect consul 110 under Trajan (with C. Erucianus Silo); ordinary consul 120 under Hadrian (with T. Aurelius Fulvus Boionius Arrius Antoninus — the future Antoninus Pius — characteristically: Severus took formally the senior place in the fasti of the year in which the future emperor was his colleague). Then the governorship of Syria Palaestina (probably in the early 130s) and the prefecture of the city (praefectus urbi) under Hadrian in the closing years of that reign. The office — the highest urban magistracy, presiding over the senatorial court, effectively head of the city's administration — was normally given to aging consulars of special standing.

The denouement at the succession of 138. At the critical moment of the adoptive transmissions of 138 (Hadrian → Antoninus Pius → Marcus), Catilius Severus, according to SHA Hadrian 24, found himself in opposition to the choice of Antoninus and was deprived of the prefecture of Rome — historians disagree as to whether this was his own frustrated claim to the succession or simply opposition to the adoption of Antoninus. His name then disappears from the sources; he died approximately at the same time (138/9), most likely in disgrace.

The connection to Marcus: marriage to Dasumia Polla. Catilius Severus married Dasumia Polla, the widow of Cn. Domitius Tullus. Tullus had adopted his niece Domitia Lucilla the Elder (Domitia Lucilla Maior, the biological daughter of his brother Cn. Domitius Lucanus); she married P. Calvisius Tullus Ruso (consul 109), and their daughter, Domitia Lucilla the Younger, became Marcus's mother. Catilius Severus was thus the stepfather of Lucilla the Elder, the step-grandfather of Marcus's mother, and Marcus's step-great-grandfather. Hence "great-grandfather" in Med. 1.4 and proavus maternus in SHA Marcus 1.4, although by blood he stood in no kinship at all to Marcus.

The adoptive connection was so formally weighty that Marcus's full childhood name included his cognomen: M. Annius Catilius Severus. The name Catilius Severus dropped out of Marcus's full names only after 138 — following the adoption by Hadrian-Antoninus and the disgrace of Catilius Severus.

Educational role

Marcus's principal attribution to Severus is the three practical principles on education (see 01-04 and the commentary): (1) do not send the child to public schools, (2) bring good teachers into the home, (3) understand that this is no place to economise. This is not evidence that Severus himself taught the young Marcus or personally selected his tutors; it is, apparently, a family principle that Marcus identifies with the figure of his great-grandfather as with the authority who set this standard. In practice the choice of particular teachers in Marcus's childhood will have lain with the mother (Domitia Lucilla, see her card) and with the consular grandfather (M. Annius Verus the elder); but the institutional principle in the frame of which the choice was made goes back to Severus.

The teachers brought in under this institutional mode are enumerated by Marcus in 01-05 (his pedagogue), 01-06 (Diognetus — painting, philosophy), 01-07 (Junius Rusticus — Stoicism), 01-08 (Apollonius of Chalcedon — Stoicism), 01-09 (Sextus of Chaeronea), 01-10 (Alexander the grammarian), 01-11 (Fronto — Latin rhetoric), 01-12 (Alexander the Platonist), 01-13 (Catulus — Stoicism) and others. This is a corpus of private teachers from the leading philosophical schools of the day, accessible only to a household at the level of resources supplied by Domitia Lucilla's fortune and the institutional principle laid down by Catilius Severus.

• 01-04 — the only direct mention of Catilius Severus in Marcus; programmatic: the three principles of education.
• In 01-17 (the closing thanksgiving paragraph) Marcus gives thanks "that I had good relatives, good teachers"; the great-grandfather is not named specifically but is implicitly included.

• SHA Hadrian 5.10 and 24.5–8 — the two principal places: the first on Catilius Severus's early service under Hadrian, the second on his disgrace at the succession of 138.
• SHA Marcus 1.4–10 — Catilius Severus called Marcus's proavus maternus (1.4); his name in Marcus's childhood name (1.10); biographical context for the early tutors.
• PIR² C 558 — the standard prosopographical entry.
• A. Birley, Marcus Aurelius: A Biography, rev. ed., Routledge, 2000, ch. 2 ("The Family"), especially pp. 31–35 — the reconstruction of the kin connection through Dasumia Polla and Domitia Lucilla Maior.
• A. Birley, Hadrian: The Restless Emperor, Routledge, 1997 — for the context of the city prefecture under Hadrian and the crisis of 138.
• R. Syme, Tacitus, Oxford 1958, app. 65 and passim — the kin network of the Antonine elite, with mentions of Catilius Severus.
• W. Eck, Die Statthalter der germanischen Provinzen vom 1.–3. Jahrhundert, Köln 1985 — for the context of governorship careers of senators of Catilius Severus's generation.