While Rome more or less "officially" fell in 476, with the overthrow of Romulus Augustulus, there were a few unconquered provinces that continued on under the pretense of Roman rule. The most well known of these is the Domain of Soissons, as it is called, which encompassed a fairly good-sized chunk of Northern France. It was ruled by its governor/magister militum,Syragius, but under the pretense of being a detached Roman province. It managed to last 10 years after the fall of Rome proper, until it was overrun by the Franks in 486. Meanwhile, in Dalmatia, Julius Nepos, who may be the last de jure Roman Emperor, ruled until he was assassinated in 480. He was considered legitimate enough to have coins minted with his name on them.
The challenge is to create more of these remnant states and/or make them last longer. Julius Nepos would be somewhat easy-he was recognized as Emperor by most his neighbors, and only lost his head after he started conspiring against the Ostrogoths who actually controlled Italy. Have him keep his ambitions more in check, and you might see a small dynasty forming.
Syragius would be much more difficult. The Franks wanted that land, and while he might be able to defeat them initially, he can't keep them out forever.
Thoughts?
The challenge is to create more of these remnant states and/or make them last longer. Julius Nepos would be somewhat easy-he was recognized as Emperor by most his neighbors, and only lost his head after he started conspiring against the Ostrogoths who actually controlled Italy. Have him keep his ambitions more in check, and you might see a small dynasty forming.
Syragius would be much more difficult. The Franks wanted that land, and while he might be able to defeat them initially, he can't keep them out forever.
Thoughts?