The blind daughter of Duke Conon of Cornwall, in Dryden’s King Arthur.
Oswald, the Saxon king of Kent, loved her, but she preferred Arthur. This caused a war between Arthur and Oswald.
During the war, Emmeline wandered into a forest and was kidnapped by Oswald, whose sorcerer, Osmond, made an attempt to seduce her. Merlin and his spirit Philidel visited her in prison and cured her sight with a magic elixir. Arthur eventually rescued and married her.
Source
King Arthur; or, the British Worthy | John Dryden, 1691