Lucius Calpurnius Piso Frugi (sometimes Censorinus), born around 180 BC, was a Roman politician and historian of plebeian origin.
He in a served a number of political roles throughout his life, beginning in 149 BC when he held the office of tribune of the plebs. During his tribunate he proposed the first law for the punishment of extortion in the provinces, Lex Calpurnia de Repetundis. As he continued his political career, he became praetor in 136 BC, and consul (along with Publius Mucius Scaevola) in 133 BC. While consul, he took command of the First Sicilian Slave War, captured Morgantina, and began to attack Henna, the origin of the uprising. Henna would be taken by Piso's consular successor the next year. He was a strong opponent of the Gracchi, particularly in relation to the grain laws of Gaius Gracchus in 123 BC. In 120 BC he was elected censor, therefore some ancient writers called him Censorinus.
He is best known for the Annales, a seven book annalistic history of Rome that spanned from the mythical founding of Rome until 146 BC. His historical account, now lost and known to us from only forty-nine short quotations or paraphrases, was written in a simple style of Latin. Later historians relied upon his work, though many did not find it satisfactory. Cicero considered his work jejune, and Livy did not consider him fully reliable, due to his tendency to moralize and politicize the histories that he recounted. Aulus Gellius, however, an admirer of the archaic, commended the work and quoted the only major fragment that has survived until today. Moreover, the early 19th-century iconoclastic historian, Barthold Georg Niebuhr, wrote that Piso was the first Roman historian to introduce systematic forgeries. Despite its shortcomings, Piso's historical work is important because it was the first time that an account was structured into individual years, making it the earliest history to follow the so-called "annalistic scheme."