Emerald Isle is a poetic name for Ireland. William Drennan (1754-1820) of Belfast claimed to have coined the name in this stanza of his poem “Erin” (1795):
Arm of Erin! prove strong; but be gentle as brave, And, uplifted to strike, still be ready to save; Nor one feeling of vengeance presume to defile The cause, or the men, of the Emerald Isle.
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The name is popular because of the deep green of Ireland’s fields and trees. See also Ireland.