Tanusius Geminus

Tanusius Geminus was an ancient Roman historian from the 1st century BCE. Very little is known of him and none of his work survives. The German classical scholar Friedrich Münzer believed he was a senator. This perspective has been criticized for lacking supporting evidence.

It is known that he wrote a treatise on history which described the Cataline Conspiracy. The historian Suetonius utilized Geminus as a source on the Cataline Conspiracy in his work The Twelve Caesars. Geminus is thought to have been politically hostile to Julius Caesar. It has been argued that because Suetonius's work is critical of Caesar, this implies his sources, including Geminus, were also opposed to Caesar. Geminus may have even compared the actions of Caesar to those of Cataline.

The historian Plutarch also utilized Geminus as a source for one of Cato the Younger's speeches. According to Plutarch, Geminus recorded that Cato considered the campaigns of Caesar in Germany to be unjustified. Plutarch claims that Geminus wrote that the Romans should turn Caesar over to the Germans following these battles. Geminus may also have been a source for Appian. It has been argued that similarities between Appian and Plutarch indicate that they share a common source, potentially Geminus.

Seneca referred to him in his epistles. He wrote: "There are books which contain very few lines, admirable and useful in spite of their size; and there are also the Annals of Tanusius – you know how bulky the book is, and what men say of it. This is the case with the long life of certain persons, – a state which resembles the Annals of Tanusius!"It has been argued that the poet Catullus may also have referenced him in his writings. He described an annalist's works as cacata charta, which can be translated as "toilet paper." Catullus calls this writer Volusius, however some historians have identified him as Geminus. This is evidenced by the remark Seneca made describing his writing similarly as subpar. Many modern scholars are critical of this theory.