When the libraries, like the Library of Alexandria, still stood throughout the Roman empire, the ancients had ready access to numerous scholars, secular & otherwise, who all supported the historicity of the Exodus,
e.g.
- Josephus
- Manetho
- Justin Martyr
- Polemon
- Apion
- Ptolemaeus
They all linked the Exodus event to the
general time frame of Amenhotep II, and the XVIII-XIX dynasties of Egypt.
Hyksos - Wikipedia
For instance,
Justin Martyr says:
Moses is mentioned as the leader and ruler of the Jewish nation. In this way he is mentioned both by Polemon in the first book of his Hellenics and by Apion son of Posidonius in his book against the Jews, and in the fourth book of his history, where he says that during the reign of Inachus over Argos the Jews revolted from Amasis king of the Egyptians and that Moses led them. And Ptolemaeus the Mendesian, in relating the history of Egypt, concurs in all this.