Byzantine Empire Guide

[Βασιλεία Pωμαίων]

Hello. I'm pretty new to CK2 and I would like to know how to restore the Pentarchy and Roman Empire on the Old Gods start. Every run so far has been a mess, and a basic guide for it would be much appreciated, especially in the starting years since it takes so long to fabricate claims on duchies and I have to take one county per war otherwise. Thanks in advance.

[Polyester™]

Convert heresey's.
Establish Vangarian guard.
Deus vult and press claim to your de-jure holdings in Italy's area.
Deus Vult your way to Antioch, Alexandria, and Jerusalem.
Fabricate on Rome. It isn't de-jure yours, don't ask why.
Claim Rome.
Mend the Schism.
Deus vult to get the rest of the required duches in the non-orthodox world.
Fabricate and claim everything else.

Become glorious Roman Empire.

[al_x_ator2411]

If you're talking about playing on ironman for the achievements, the CKII wiki has a very detailed guide for each start (including the Old Gods one).

http://www.ckiiwiki.com/Roman_Empire_walkthrough