LEAP DAY: It was Julius Caesar who modified the Roman lunar calendar into an Egyptian-style solar calendar, which included an intercalary day every four years. This is the “Julian Calendar.” In 1582, Pope Gregory XIII established the “Gregorian Calendar” to accommodate a long-term error in the Julian Calendar, establishing that there would NOT be a leap day in most centennial years, except for only one every 400 years. February 29, 2000 was the first centennial leap day since 1600, but was overlooked by the media, and that fact went completely unnoticed and unreported.
Read more from our friends at Classical Astronomy . . .
And a fun video explanation of how leap year works.