Clement of Alexandria (c. 150-215): “But those who are ready to toil in the most excellent pursuits, will not desist from the search after truth, till they get the demonstration from the Scriptures themselves.” (Stromata, Bk. VII, ch. 16)
By the way, Matheson notes in a footnote that Clement declares the legend of Mary’s perpetual virginity as false, despite the claims of some that this was a universally accepted belief.
(The Shape of Sola Scriptura, 24)