Ainigmata Ostraka on Messara in Assassin's Creed Odyssey Assassin's Creed Odyssey Guide and Walkthrough

There is only one Ainigmata Ostraka on Messara. This one is called Till Death Do Us Part.

Till Death Do Us Part

The location of this Ainigmata Ostraka: The first part of this Ainigmata Ostraka is in the Temple of Poseidon. A small water body can be found on the right side of the temple - the tablet is inside of it.

Puzzle solution: Head south and look for the tall tree. The item is on the blanket located right next to that tree.