Over the Edge of the World

A Note on Dates

Dates are given in the Julian calendar, in effect since the time of Julius Caesar. With modifications, this calendar was adopted by Christian churches around the world, including those in Spain.

Sixty years after the completion of Magellan’s voyage, in 1582, Spain, France, and other European countries migrated to the Gregorian calendar, decreed by Pope Gregory XIII and designed to correct incremental errors in the Julian system. It took more than two centuries to complete the transition to the new calendar throughout Europe, since Protestant nations resisted the change. To correct for accumulated errors, ten days were omitted, so that October 5, 1582, in the Julian calendar suddenly became October 15, 1582, in the Gregorian.

In addition to this calendar shift, Magellan’s voyage had its own record-keeping issues. The dates of various events recorded by the two official chroniclers of the expedition, Antonio Pigafetta and Francisco Albo, occasionally diverge by one day. The discrepancy may be due to human error, and it may also have been caused by the way each diarist reckoned the day. Albo, a pilot, followed the custom of ships’ logs, which began the day at noon rather than at midnight. In contrast, Pigafetta used a nonnautical frame of reference in his diary. Thus, an event occurring on a given morning might have been put down a day apart in the records maintained by the two.

Finally, the international date line did not exist before Magellan’s voyage. (It now extends west from the island of Guam, in the Pacific Ocean.) As Albo and Pigafetta neared the completion of their circumnavigation, they were astonished to note that their calculations were off, and their voyage around the world actually took one day longer than they had thought.