Hail Caesar is written by the hugely talented Rick Priestley who is something of an expert in Ancients gaming. Partly because of his studying in antiquities but some would say that it's also because he was there for the most part.
So aside from firsthand experience of classical civilizations what else do you get?
Warlord Games - Hail Caesar - Early Imperial Romans: Veterans
$41.00
Warlord Games - Hail Caesar - Late Republic Caesarian Roman Starter Army
$179.99