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It is known that the ancient Bulgarians knew the basic laws of motion of the planets and the Earth around the Sun perfectly, and because of that they possess the most impeccable calendar ever created.

The ancient Bulgarian calendar is based on observations of Jupiter and the Sun and is more precise than the modern Western(Gregorian) calendar we use today.

Under the ancient Bulgarian Calendar system, the year has 365 (or 366) days, 4 quarters, 52 weeks and 13 months, of which the 13-th consists of only 1 day (the New Year Day). Therefore, every year, the same date always falls on the same day of the week! In the 1970s, non-Bulgarian scientists raised the question in UNESCO, whether this calendar should be proclaimed the one for the entire world.

The ancient Bulgarian calendar proves to be the most accurate calendar system in existence.

In the ancient Bulgarian chronology, there are periods of 3, 10, 12, 17, 19, 21, 30, 47, 50, 53, 300, 600, 4332, etc. ancient Bulgarian years that are used both as denominators and intervals of time. The longest one is of 6328 ancient Bulgarian years. It is mentioned in the fragmentary inscription of Khan Omurtag and refers to the year 823 AD. The text consists of 14 lines, probably the concluding part of a contract between Danube Bulgaria and the Eastern Roman Empire. The inscription is carved with beautiful letters on a marble stone most probably from the capital town of Pliska. Here is what it reads:

“[…of the ruler] the name is [Khan Omurtag Juvigi]. The year of the appearance of the true god was
6328. They made a sacrifice and they swore in the written in the books [mutual contracts]…”

This historic source may be accepted as a proof of the early beginning of the chronology of the Bulgarian calendar. According to the counts of the great Bulgarian historian Professor Vassil Zlatarski the beginning is the year 5505 BC. Therefore, we can calculate that the year, 2001 AD, is the year 7506 of the ancient Bulgarian chronology. Thus, the Bulgarians are the people with the most ancient system of measuring time – a fact, which indicates their early civilizing force.