The Church Fathers believed in Sola Scriptura:
"They [heretics] gather their views from other sources than the Scriptures...We have learned from none others the plan of our salvation than from those through whom the Gospel has come down to us, which they did at one time proclaim in public, and, at a later period, by the will of God, handed down to us in the Scriptures, to be the ground and pillar of our faith" - Irenaeus, Against Heresies, 3.1.1
Notice what the ground and pillar of truth was to Ireanaeus ...THE SCRIPTURES
"I beg of you, my dear brother, to live among these books [scripture], to meditate upon them, to know nothing else, to seek nothing else."
- Jerome (Letter 53:10)
Sola scriptura..
Seems Luther and Calvin had some good ole catholic company