Old Russian (Byzantine) chronology system
This calculator is useful not for everyone, but to know that he is doing and why it will be interesting to everyone.
So, before you a Byzantine system of chronology. If you miss the whole encyclopedia of Byzantine history, about the method of calculation, it is possible to come at once to a simple example, which can make the calculator.
There are 2 styles, which you can find any you entered date and find out how many years is the creation of the world. These two styles for different feel. The thing is that the new year, each of these styles do not match the new year of the Christian era. According to the March style new year note at 2 months later, and in the September, on the contrary, the whole 4 months earlier.