Possible to get mare nostrum as kingdom of jerusalem?

[N0Face]

Hi.
I'm playing as provence and it's going really great. I'm going to get the "Good King René"-achievment by restoring the kingdom of jerusalem.
My question is now, is it possible to also get the mare nostrum-achievment?(i.e. is it possible to first form Jerusalem and then after that form the Roman Empire?)

Thanks in advance!

 

[mag_zbc]

The only tags excluded from forming Roman Empire are Papal State and Holy Roman Empire, so yes

 

[herrhals]

BUT WHY?!

 

[Zohtun]

Wow talk about doing it the hard way.

I mean you CAN do it but by jove...WHY?