Who was known as "the Navigator" as noted in the nonfiction book, The Age of Bede?

St. Brendan, a monk who lived from 484 to 577, was known as "the Navigator." He was an early Irish monk and saint and is the main character in a legend about his voyage to the "Isle of the Blessed," as contained in The Voyage of St. Brendan. The Voyage or "Navigatio" was widely read in the Middle Ages.