On the Homebrewed Christianity podcast, Tripp Fuller quotes Process and Reality by Alfred North Whitehead in a conversation with Brian McLaren (22:20).

When the Western world accepted Christianity, Caesar conquered; and the received text of Western theology was edited by his lawyers. The code of Justinian and the theology of Justinian are two volumes expressing one movement of the human spirit. The brief Galilean vision of humility flickered throughout the ages, uncertainly. In the official formulation of the religion it has assumed the trivial form of the mere attribution to the Jews that they cherished a misconception about their Messiah. But the deeper idolatry, of the fashioning of God in the image of the Egyptian, Persian, and Roman imperial rulers, was retained. The Church gave unto God the attributes which belonged exclusively to Caesar.

Whitehead, Alfred North. Process and Reality (Gifford Lectures Delivered in the University of Edinburgh During the Session 1927-28) (p. 342). Free Press. Kindle Edition.

https://en.wikipedia.org/wiki/Process_and_Reality

Apparently this book is the one that contains his quote about western intellectual endeavors being footnotes to Plato.