The Annals of the Four Masters is a history book written between 1632 and 1636.
The books contains information about
the family history of the kings and chieftains,
battles and wars with the Vikings, Normans and English invaders.
The Annals of the Four Masters mentions Rathdown
to the North of Greystones.
The Annals say King Heremon built a rath there towards the end of Bronze Age (500BC)
You can read more about the Annals of the Four Master on the ‘Ask about Ireland’ website.