Brewer's: Iberia's Pilot
Christopher Columbus. Spain is called “Iberia,” and the Spaniards the “Iberi.” The river Ebro is a corrupt form of the Latin Iberus.
Launched with Iberia's pilot from the steep, To worlds unknown, and isles beyond the deep.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894