The republican jurists had already extended the meaning of iniuria (unlawfully) to culpa (negligence): Dig. (p. 72) and Gaius Institutes, Book 3.211. Gaius interprets dolus (fault) as being intentional and with malice (Mens rea); Paul adopts Gaius' terminology in his commentary (intentional and with malice); culpa is negligence. In contrast to the other delicts where only dolus is actionable, the Lex Aquilia recognizes culpa levissima Dig. 9.2.44 (p. 96). Negligence is first developed in the Lex Aquilia and only later extended to other areas of law.

Modern civil law recognizes negligence when a person is able to recognize the unlawfulness of his behavior and could have had the opportunity to act otherwise.

The Roman jurists leaned towards a universal measure later called the Homo constans, e.g. Dig. 9.2.31. Homo diligens; paterfamilias diligens.
Page numbers refer to Justinian, The Digest of Roman Law: Theft, Rapine, Damage and Insult (Penguin Books).

"Magna negligentia culpa est, magna culpa dolus est," Paul, Dig. 50.16.226  "A gross negligence is culpa, and a gross culpa is criminal malice."

Comparative responsibility (fault[Culpa]): Compares fault of Actor and Reus

Strict liability: Reus has no fault (Culpa) but is liable

Contributory Negligence: Actor has a degree of fault [Culpa]