Someone tell me how the Roman/Greek, America, Egypt & Japan themes fit into the Chrono World cause I don't get it. Where would they fit?
There are wide ranges of the timeline that are never explored in the series. Roman/Greek could fit anywhere between 12,000 BC and 600 AD. America could fit anywhere between 1020 AD and the end of time really... and Porre's colonization of El Nido in 920 AD could have some Christopher Columbus vibes too. Japan already makes its way everywhere in more of less subtle ways (Zeal's worship of the Sun Stone sounds like animism; Crono uses katanas and Melchior forges them; Radius is essentially a samurai, etc.), and it's not like Japanese developers care whether Japan fit in their stories or not anyway, they'll still insert it if it they want (Wutai in FFVII and Yamato in Valkyrie Profile stick out like sore thumbs in their worlds). Egypt is more difficult and I can't think of any JRPG that has an Egyptian civilization apart from Valkyrie Profile, but still it could easily fit between 12,000 BC and 1 AD.