What is regarded as Cicero's earliest surviving work?

The earliest surviving work of Cicero is widely considered to be "Pro Sexto Roscio Amerino." This speech, delivered in 80 BC, was Cicero's first major public oration and marks a significant moment in his legal career. In this work, Cicero defends Sextus Roscius, who was accused of murdering his father. The oration showcases Cicero's skills in rhetoric and legal argumentation, as well as his growing prominence in Roman public life.

"Pro Quinctio" is also a defense speech but was delivered later in Cicero's career, meaning it cannot be regarded as his earliest work. The "Philippics," a series of speeches against Mark Antony, were composed much later and reflect a different phase of Cicero's political life, as does "De Re Publica," which is a philosophical work on the state and governance. Both of these works are not considered early in Cicero's oeuvre and thus cannot be classified as his earliest surviving piece.