St. Brendan, nicknamed the Navigator, was an Irish abbothead of a monastery or abbey of the 500s who became the hero of legendary ocean voyages and the patronspecial guardian, protector, or supporter saint of seafarers. An eager traveler, Brendan journeyed to various lands bordering on the Atlantic Ocean. Some 400 years later, his travels were made famous in the Navigatio Sancti Brendani (Voyage of St. Brendan), a fictionalized work that became one of the most popular books of the time.

In the Navigatio, Brendan and a group of monks make an amazing trip in search of the "Promised Land of the Saints." According to the story the monks wander the ocean for years, stopping at different islands and experiencing various adventures. Eventually, they reach their goal. Many of the islands described in...