Did you know that Julius Caesar is generally acknowledged as the father of the leap year? Back in the day, the Roman calendar only had 355 days (!) and was evidently shorter than the solar year (the time it takes for the Earth to orbit around the sun—365 ¼ days). In order to keep the calendar aligned with the seasons, the Romans would add a month here and there (what a mess!)… until Caesar became dictator and sorted things out by consulting with astronomers in 46 BC. It was decided that a day should be added to the calendar every 4 years to make up for the discrepancy between the lunar and solar calendars. The Leap Year came into effect in 45 BC.
Julius also took the opportunity to rename one of the months in the calendar. He picked Quintilis, the fifth month of the year (which started in March back in those days, not January) and renamed it after himself… a month we all know today as July.
I have simplified things a bit, but that’s the upshot of it all!