Cóis Dara is sixty acres of land owned by the Noble House of Prince in Ulster Province of the County Down of Ireland, including their family home, Prince Manor. The land, dominated by their country's native tree, majestic, spreading sessile oaks, earned its name through them.
It's long been known as a haven for the Princes, who, like the oak trees, have a family history of strength, durability under pressure and unity reflected by their family motto .
They have a long-running family tradition where, on each family member's twentieth birthday, he or she is given a sessile acorn from one of their parents to plant anywhere they wish on their home grounds. The chosen member infuses the acorn with his or her own magic and compassion before planting it, marking it with his or her individual signature, a way of allowing that person's love to live on in the land.
Appearances: Bua no Bas, Coming Back To You (chapter 11)