Lex Iulia and Papia Poppaea the maritandis ordinibus, actually the lex Iulia of Octavianus (= Emperor Augustus) (18 BC), changed and extended in 9 AD. by the consuls Marcus Papius Mutilus and Quintus Poppaeus Secundus. She intended the promotion of marriages by connecting privileged children (ius liberorum). Extrajudicial sex between infants became punishable. (More about this law in Sexuality at the ancient Romans # Legal Measures.)

It was not clear in ancient times which arrangement belonged to any law, bringing together both laws like lex Iulia et Papia (Institutiones of Gaius) or lex Iulia miscella (Codex Iustinianus). Although August had already found that these laws were missing their goal, they were only lifted in 531/534. Ancient sources

wiki