In 46 B.C.E., Julius Caesar implemented the Julian calendar, which was 11 minutes longer than a solar year. By 1582, those 11 minutes each year had added up to 10 days. Pope Gregory XIII aligned the calendar with the solar year by declaring October 5, 1582, to be October 15, 1582, in the Catholic regions of the world, thus correcting for the 10 lost days.