Silver branch

The Silver Branch or Silver Bough is a symbol found in Irish mythology and literature.

Featured in the Irish poem The Voyage of Bran, it represents entry into the Celtic Otherworld, which the Welsh called Annwn and the Irish Tír na nÓg: "To enter the Otherworld before the appointed hour marked by death, a passport was often necessary, and this was usually a silver branch of the sacred apple-tree bearing blossoms."

The branch is also associated with Manannán mac Lir, an Irish sea deity with strong affiliation to Tír na nÓg. As guardian of the Otherworld, Manannán also has strong ties with Emhain Abhlach, the Isle of Apple Trees, where the magical silver apple branch is found. Both the branch and Manannán are featured in His Three Calls to Cormac, or "Cormac's Adventure in the Land of Promise." Here, he appeared at Cormac's ramparts (at Tara) in the guise of a warrior who told him he came from a land where old age, sickness, death, decay, and falsehood were unknown (Tír na nÓg). The king was given a "branch of silver with three golden apples on his shoulder. Delight and amusement to the full was it to listen to the music of that branch, for men sore wounded, or women in child-bed, or folk in sickness, would fall asleep at the melody when that branch was shaken."

Also, in Immacallam in dá Thuarad, or The Dialogue of the two Sages, the mystic symbol used by gods, fairies, magicians, and by all initiates who know the mystery of life and death, is thus described as a Druid symbol:–'Neidhe' (a young bard who aspired to succeed his father as chief poet of Ulster), "made his journey with a silver branch over him. The Anradhs, or poets of the second order, carried a silver branch, but the Ollamhs, or chief poets, carried a branch of gold; all other poets bore a branch of bronze."

...
Wikipedia