If I remember correctly from my hazy years of school philosophy classes, it was Thomas Aquinas who suggested it. Who was a friar, so that's why the assumption of the religion.

Also, I understood the core idea being that God isn't what IS the beginning, but that the point where human mind can't comprehend beyond is God. Which, back then, and even now, I considered to be a lazy copout for a philosopher, as the point of a philosopher is to test the limits of our understanding.

Then again, for friar to state that the end solution is not god for their thinkings, at that time and place, would've probably result in being positioned as a centerpiece of a bonfire.