Roman history is taught everywhere and served online by a mix of ageing university pages and thin content farms. Something authoritative, well illustrated and properly structured would find its audience immediately, particularly among students and teachers. The subject is one of the most consistently popular in history: school curricula, university courses, documentaries, podcasts, games, novels, and a general readership that never diminishes. The .org is exactly right for it. Classical studies live in universities, museums, learned societies and archaeological institutes, all of which use that extension.

The definite article does real work. It makes the name read as the subject itself rather than as a description, which is the right register for an authoritative resource. It sounds like the reference rather than a site about the reference. The Roman Empire is among the most studied and most popular subjects in human history: school curricula, university programmes, documentaries, podcasts, games, and a readership that hasn’t diminished in five hundred years of printing.