Eleanor f. Of uncertain origin. The name of Eleanor of Aquitaine, known as Provençal as Alienor, is often explained as Latin alia 'other' + Aenor, the name of her mother, but as there are possibly examples which pre-date her, this cannot be the complete story.
The name of a 12th C queen consort of France and England, a 12th-13th C queen consort of Castile, a 13th C queen consort of Castile, two 13th C queens consort of England, a 13th C queen consort of Denmark, two 14th C queens consort of Aragon, a 14th C queen consort of Portugal, a 14th-15th C queen consort of Navarre, a 15th C queen consort of Portugal, and a 16th C queen consort of Portugal and France.
Though the names are unrelated, Ellen over time came to be considered a variant or a pet form of Eleanor.