Ernest Gordon Rupp said of Thomas Monck’s Cure for the Cankering Error of the New Eutychians (1673), “No high churchman, no orthodox Anglican, not Daniel Waterland himself produced an abler defence of catholic doctrine” (Rupp, 1986). Monck’s Cure was a biblical and theological polemic against the rising tide of Antitrinitarianism in England and the emergence of heretical Christology within his own denomination. Rupp’s assessment is striking since Monck was a General Baptist pastor and farmer with no access to university training. Nevertheless, Monck marshaled the language of the ecumenical creeds as well as the writings of the early church fathers and the Reformed Orthodox to defend the doctrine of the Trinity, particularly the person of Christ. To date, Monck’s Cure has received little attention, though some work has been published on his use of the ecumenical creeds and the early church fathers (Stamps, 2017; Owens, 2020). Very little has been published on Monck’s use of Reformed Orthodox writers such as Calvin, Perkins, Vermigli, and Zanchi, who appear prominently in his polemic. Monck’s use of these theologians demonstrates that, although Monck was a General (Arminian) Baptist pastor and farmer, he drew deeply from both ancient and modern sources for his defense of the Trinity. Monck appealed to Reformed Orthodox writers to defend the doctrine Trinity and to demonstrate that his Trinitarian theology was in continuity with the Protestant tradition.