1 Pretender and 1 Prophet?

[Arryn]

To add to Argitoth's reply, pretenders who are not immortal or immortals who die outside of friendly dominion need to be Called. If immortal and within friendly dom, the pretender will reappear the next turn in your capital.

The opportunity to create a new prophet after an old one has died takes 6 months of waiting, IIRC.