The Old World is a reference to those parts of Earth known to Europeans before the voyages of Christopher Columbus; it includes Europe, Asia and Africa.
Whence Rome lost its nation state innocence, hence the moral high ground of civilization, and descended into raw feudal fascist expansionism. In 6 bite sized chunks of 10 minutes.
And oozing with parallels applicable to today.
The tight British accents make me expect 'm to pause for a steamin' cuppa all the time though.