There is no reason that such a set up by calculating the science of astronomy. And is widely used for over two thousand years. They are not related to religion. Or the politics of any of
There is a reason that the date determined by the calculated astronomical science and is popular for more than two thousand years ago. It is not associated with religious or political doctrine of any nation
The reason is that the Day established by the astronomical calculation with science is a popular and much-used, two thousand years ago, and is not associated with the cult of religion, or any other nation of the city