This edition combines two books of the famous Russian scientist Thaddeus Frantsevich Zelinsky (1859-1944): the book "Ancient Greek Religion," first published in 1918 and its continuation "The Religion of Hellenism," which was published in 1922. On their pages, Zelinsky tried to build a special world of evidence, deduced by him from the thesis: "Ancient religion is the real old testament of our Christianity."