Stolen epitaph

1-Speak with the Achivist in Alexandria

2-Read the Georgraphy book for the next clue

3-Speak with the barman in Alexandria who will give you a clue about a pointed boulder outside of town. The town is actually Cairo not Alexandria. (Only way I found this out is by looking at every Landing Port map on Wiki around Alexandria and finding those with pointed boulders... )

4-Go to the pointed boulder in the NE section in the outskirts of Cairo

5-The tablet is nearby... use Observe skill then Search.