Christian religion is 33% of the world religion. Not a simple majority. http://www.adherents.com/Religions_By_Adherents.htmlThis is nonsense. Christianity is still the predominant religion in the world today. It is about twice as much as the next predominant religion -- islam -- and is a firm majority in the western hemisphere.
The democracy concocted by the greeks was very different from what we know of it today. It was inevitably synthesized with early christian thought, which at the time, was the religion of slaves and the very dregs of society. Only through the ethical teachings of christianity did we gradually accept the members of the lower strata of society as having a say in political dynamics.
In the political philosophies of the west, the concept of natural law is inseparable. While natural law was first thought of by the greeks, this concept came to be used more on the natural sciences. To say that every man is equal as a consequence of natural law would have been an unthinkable outrage in classical greek thought. It was the christians who applied the concept of natural law in political philosophy.
Early Eastern philosophies that pre-date Christianity had many of the same tenants that the Christians claim today.