Novatian was a priest of Rome in the third century who wrote a commentary on the Rule of Faith, commonly titled, On the Trinity. Although the document is not well known outside of the field of early Christian studies, it made an important contribution to the doctrine of the Trinity in the early Church, and as several scholars have maintained, it helped set the stage for the definition of the faith known as the Nicene Creed. Novatian would eventually find himself at the center of a controversy which led to a schism of the Church, and so his works were relegated to obscurity for centuries. However, in its time, Novatian's On the Trinity was the epitome of Roman theology, and as some have argued, it was even ahead of its time. The present volume contains the complete works of Novatian translated into English, with an introduction and full bibliography of Novatian studies. This new translation takes into account the latest scholarship on Novatian, and brings the documents up to a new level of clarity and readability. The source text of this volume appeared in Corpus Christianorum Series Latina as Novatianus - Opera quae supersunt (CCSL 4), edited by G. F. Diercks. References to the corresponding pages of the Corpus Christianorum edition are provided in the margins of this translation.