Here is the full list of all 20 Argonus and the Gods of Stone achievements.
Talk to five gods.
Steal two things from their owner.
Ride a stallion three times.
Talk to four gods.
Raise the dead.
Talk to three gods.
Find and place all the mosaic pieces.
Talk to two gods.
Talk to one god.
Find all the broken pieces of wrecked ships.
Light all sconces and braziers.
Unearth a certain ancient skull.
Obtain every takable object on the isle.
Read all journal entries.
Complete all Achievements.
Talk to every god on the isle.
Teleport to and from every temple on the isle.
Set free the souls of all the Argonauts.
Set free the souls of all the isle's inhabitants.
Learn to use a forge.