The world remembers Julius Caesar for many things: his military campaigns, his affair with Cleopatra, his dramatic death on the Ides of March. We also remember him for setting up the basic calendar that the western world has used ever since. And the Roman Senate named the seventh month in the calendar in his honor: July.

Before Caesar’s reforms, Rome used a calendar that was based on the cycles of the Moon. But such a calendar drifts with respect to the seasons. Extra days were added to try to correct the difference. By Caesar’s time, though, the calendar was a big mess.

So Julius Caesar looked to his newly conquered province of Egypt. Thousands of years earlier, the Egyptians had devised a calendar based on Earth’s orbit around the Sun — the first 365-day solar calendar.

Caesar adopted this system, but he kept the names of the months from the Roman calendar. The seventh month was named Quintillis. The name actually means fifth month, because in the original Roman calendar, the year began with March, not January. After Caesar was assassinated, his successor, Augustus Caesar, thought having a month named for the emperor was a good idea. So the month of Sextillis was changed to August in his honor. Later emperors tried the same trick, but with no luck. Senators realized that they\'d eventually run out of months, so they stopped the practice. But the name of Julius Caesar lives on — in the seventh month of the year.

Script by Damond Benningfield

Support McDonald Observatory