Extra Catholicum

"The label “extra Calvinisticum”, applied to the affirmation that in the Incarnation the Eternal Son of God was united to but not restricted to his humanity, is misleading, to say the least. There is nothing uniquely Calvinist about the doctrine, for as a means of interpreting the Biblical witness to Christ it had a widespread and ancient usage.

There is a direct liaison from Calvin to Lombard and especially to St. Augustine. That he learned the doctrine from other portions of the tradition cannot be proved from his writings, but it was in fact almost universally confessed – from Origen and Theodore of Mopsuestia, to Athanasius and Cyril, to St. Thomas and Gabriel Biel….

If one wished to add to the terminological explosion which threatens and delights the theological world, one might coin “extra Catholicum” or “extra Patristicum” as being more appropriate than “extra Calvinisticum.""

E. David Willis, Calvin’s Catholic Christology: The Function of the So-Called Extra Calvinisticum in Calvin’s Theology Studies in Medieval and Reformation Thought volume 2 (Leiden, E. J. Brill, 1966), p60

See also Peter Leithart's summary of Barth on this.