The gens Catilia was a minor plebeian family at ancient Rome, found from the first century BC and throughout imperial times.
The most illustrious of the Catilii was Lucius Catilius Severus, consul in AD 120, and one of the ancestors of Marcus Aurelius.
[3] The surname Catulus indicated a puppy, and was one of an abundant group of cognomina derived from the names of animals and everyday objects.
An early family of this gens used Gaius and Titus, but otherwise the latter name was one of several praenomina found only once or twice among the Catilii, such as Aulus, Marcus, Numerius, and Quintus.
Although many Catilii bear typical Roman cognomina, the only distinct branch of the family to appear in history used the surname Severus, originally designating someone stern or severe in manner.