Our earliest surviving literary reference to Pontius Pilate is found within the writings of the diaspora Jew, Philo of Alexandria. His Embassy to Gaius (or Legatio ad Gaium) describes how Pilate offended against the Jewish Law by setting up aniconic shields in Jerusalem. The Jewish leaders appealed to Tiberius who ordered Pilate to remove them (§§ 299–305). The incident is found within a letter supposedly from Agrippa I to Gaius Caligula, attempting to dissuade the Emperor from setting up his statue in the Jerusalem Temple (§§ 276–329). However, modern scholars are agreed that the letter as we now have it is clearly the work of Philo himself. It is perfectly feasible that Agrippa wrote a letter to Gaius and also that Philo, who was in Rome at the time, knew something of its contents. Yet, in accordance with historiography of his day, Philo has presented the letter in his own stylistic terms.

Philo's account of Pilate is historically important in that, although belonging to Egypt, he was a contemporary of the events which he relates in Palestine. He would also have had access to reasonably reliable information through his family connections with Agrippa. However, Philo's ‘historical’ writings, comprising the Embassy to Gaius and the In Flaccum, are marked by strong rhetorical and theological concerns. This is particularly prominent in his assessment of the character and actions of Roman Emperors and officials. Therefore, whilst Philo's account of Pilate doubtlessly contains a core of historical fact, his description of Pilate's character and intentions has very likely been influenced by his rhetorical objectives.