Publius Sittius is mentioned in De Bello Africo, the history of the civil war in Africa, seen by a supporter of Caesar (Chs. 25, 36, 48, 93, 95 & 96; the author is unknown). It is not clear from this text how Sittius came to be in Africa or why he had allied himself with Caesar and not Caecilius Scipio. His first recorded action (Ch. 25) in the history joins forces with King Bogus of Mauritanea (or Bocchus II), attacking and forcing the surrender of Cirta, the richest town within the Kingdom of King Juba I, an enemy of Caesar who had already begun to send his army to support Scipio. This event forced King Juba to adjust his plans and return part of his army to defend his territory thereby diminishing Scipio's available manning.
It is recorded that Sittius enjoyed several successes against the enemies of Caesar (Ch. 36), including later the defeat of Juba's forces under Saburra, and the successful ambush of Faustus Cornelius Sulla and Lucius Afranius as they attempted to flee to Spain following their defeat by Caesar at Thapsus (Ch. 95). He is also credited with the sinking of Scipio's fleet (Ch. 96) at Hippo Regius where Scipio perished having also taken flight from Caesar after Thapsus. He notably assists Caesar through the campaign by diverting the attention and full strength of King Juba's forces (Ch. 48), preventing him from focusing his resolve entirely on the annihilation of Caesar.
While it is clear his efforts support Caesar, and he is in the service of Caesar, at no point in the text does it mention that Sittius is commanded by Caesar although it could be expected that communications existed between them or their subordinates. After the end of the campaign Caesar grants him lands at Cirta, within Western Numidia where he founded a colony with his followers the Colonia Cirta Sittianorum cognomine and settled there.
- "Publius Sittius and Caesar's Revenge". History Today. Retrieved 2013-09-01.
- Caesar Alexandrian, African and Spanish Wars, with an English translation by A.G. Way, M.A., Loeb Classical Library, Harvard University Press MCMLV.
- "Cirta, called the Sittians' Colony", Pliny the Elder, Natural History, Book V; 22 or II, 1 (according to the two different numbering conventions).
- "The Civil War" by Appian, Book IV, 54.