1 - Between Dublin and Rathdown
2 - King's Hall
3 - Dublin Town
4 - South of Dublin Town at the Coast
Between Dublin and Rathdown
UI NEILL Artifact
On the land strip between Dublin Town and Rathdown is a stone structure.
The Artifact is behind a destructable wall. But no oil flask around. It is behind the wall.
Use the two trees or the tall stick to climb on the rope above the structure.
On the southern wall (screenshots) you can destoy a wooden wall.
Now you can see and shoot the oil flask.
IRISH CYCLE PAGE
Tatha De Danann
On the second floor of the King's Hall, in the bedroom is the Irish Cycle Page.
Reward: Pict Scheme (head) tattoo.
Screenshot below show start and end point.
Dublin Hoard Map
At the southeastern coast, south of Dublin Town, there is Treasure Hoard map inside a locked cave.
The key is inside the water right by the small pier.
Now you can unlock the gate and get the Dublin Hoard Map.
The Treasure is in the field east of Rathdown (see screenshots below)
Reward: Na Pucai Scheme (Tailpiece)