The author Adrian Goldsworthy wrote in ‘Caesar’: “Whether or not Caesar was actually the father is impossible to say with absolute certainty and would require far more intimate knowledge of the queen’s life than we possess. The majority of ancient sources who commented on the matter seem to have accepted that Caesarion was the dictator’s child, but then these authors all wrote considerably later. Suetonius does mention that after Caesar’s death his long-time assistant and confidant Caius Oppius wrote a book to refute this claim.”

But Goldsworth goes on to say that, on balance, a better case can be made for assuming that Caesar was, or at least believed he was, the child’s father, but he was “illegitimate, not a Roman citizen and only an infant.” Which could perhaps explain why the boy wasn’t even mentioned in his will drawn up in the last months of his life. He’d also turned his attention to the grandson of his sister, Caius Octavius, who went on to become Emperor Augustus.