Robert Guiscard offers and interesting possiblity. Let the man live to be seventy-five or eighty.
More later time's up.
Guiscard nearly united the thrones of Byzantium and Sicily. Only his sudden death from illness stoped him. Unifying those thrones and perhaps the Holy Roman crown of the Western Empire as well (he nearly got both crowns), Guiscadr could have created a neo-Roman empire. The possibilities for adventure run so many directions from there.