It was one of three laws introduced by the Romans during the Social War (91–88 BC) between Rome and her Socii (allies), where some of Rome's Italic allies rebelled and waged war against her because of her refusal to grant them Roman citizenship.
It granted Latin Rights (ius Latii) to these peoples as a reward for siding with the Rome during the Social War.
They included: A) Ius Commercii (right to trade), "a privilege granted to Latin colonies to have contractual relations, to trade with Roman citizens on equal terms and to use the form of contracts available to Roman citizens".
[3] In addition to this, the law granted Roman citizenship to the magistrates (officials) of the local towns.
This measure was preceded by the Lex Iulia de Civitate Latinis et Socii Danda of 90 BC which granted Roman citizenship to all the citizens of Italic towns which had not rebelled against Rome, and the Lex Plautia Papiria de Civitate Sociis Danda which granted Roman citizenship to Italian communities which had rebelled against Rome during this war.