The ancient Egyptians did not. They used a 365 day calendar that consisted of 12 months of 30 days plus an extra 5 days at the end. But because they didn't ha

The ancient Egyptians did not. They used a 365 day calendar that consisted of 12 months of 30 days plus an extra 5 days at the end. But because they didn't have any leap days, the calendar would gradually cycle through the year relative to the seasons.