What you are about to read will tell you of everything about  the ancient calendars of the Egyptians and Mesopotamians. The Egyptian calendars were very important to the Egyptians and played a big role in life. The Mesopotamian calendar also played a major part in the legacy of Mesopotamia. They both pursued the different functions of the understanding of astrology. We will be comparing the two. 
 

                                        The Egyptian Calendar
                   
 
        One of the things that played a big role in the Egyptian calendar was the Nile River. The Nile River flows through Ethiopia to the Mediterranean Sea. If this river had not been here thousands of years ago, then Egypt would be basically just a vacant desert, with no life. But the plants and land in the Nile Valley are all there because of the floods the Nile experiences. In fact, it was studied by the ancient Egyptians that it has been flooding for the past 5000 years, annually, according to Egyptian-recorded time. Without the river, all that fertile ground would not be lying there.
 
        To stay alive and to save all their plants and property, the most important thing the Egyptians needed to know was when. When is the Nile going to flood? This is one of the great scientific achievements of Egypt which kept them alive. Every 365 days, right before sunrise, Sirius, a star, rose on the eastern side horizon. And the lunar calendar is based on this. So what they would do is they would start counting a year when they would see a new moon right after Sirius. There were 12 months, each month containing 29 1/2 days, having 354 days. And even sometimes, just to be safe, they added another month to the calendar so that they could ensure that the two factors, the Nile and the calendar, always matched each other, in terms of when the Nile would flood, and the date. Later, little things were upgraded, like the calendar becoming more accurate, having 7 days in it. One thing that was forbidden for astronomers by their guardians was to correct the calendar, as it is 365 1/4 days long, and add one more day every four years, which is called a leap year.
 

                                     The Mesopotamian Calendar
 

        Sumer was an area located in Mesopotamia. The Sumerians were the first to develop a 30-day lunar calendar. This lunar calendar was developed by the priest-astronomers who interpreted the movement of the stars. The Sumerians not only invented the lunar calendar, they also invented the first writing system, cuneiform.
 
        After 700 years of existence, the Sumerians fell. Babylon though, arose in their place. But in 1750 BC., during the Hammurabi kingdom, an improved Sumerian calendar was developed. This calendar was known as a Babylonian calendar.
 
        This Babylonian calendar had 354 days per year. Each year had 12 alternating months of 29 days and 30 days. But this calendar was missing 11 1/4 days. They needed to add the 11 1/4 days to the calendar so that it would match the 365 1/4 day solar year. If this was corrected, the seasons would match their dates somewhat each year. They corrected this problem by adding 2 months and 7 days every 19 years.

 
                                       The similarities of the two is that they both had seven day weeks and 12 months. The main similarity is that, they both had calendar systems. They both were round, having a pointer pointing to which ever hieroglyph. On the circle is hieroglyphics meaning different things.

                     There are also differences between the two.  The Egyptian calendar was more based upon the annual floods of the Nile River and the Mesopotamian calendar was based on a more accurate study of astrology by the Mesopotamians. The Nile River of Egypt was like the center point of astrological sciences studied by the Egyptians. Mesopotamia calendars had alternating months of 29 and 30 days. Sirius, the main star in the Egyptian belief system, was part in it too. They used Sirius as a guide to tell when the new year is present.  The first time Sirius was replaced by the new star, they declared that it the new year.
 

                   These are some of the many differences and similarities of the Egyptian and Mesopotamian calendars. Both the Mesopotamians and Egyptians were very creative and smart. I think that the calendar played a very big role in both these great civilizations. The knowledge acquired to perform these great achievements had to require a civilization that has very advanced.