From Monachos.net
The De Trinitate ('On the Trinity') of Hilary of Poitiers is among the most important and abiding works of the married bishop consecrated c. AD 353. Exiled by Constantius II following the Arian-majority council at Béziers in 356, where he refused to condemn Athanasius, bishop Hilary composed this text in Phrygia prior to his return in 360. Often considered an 'introduction of Eastern theology to the West' on the matter of the Trinity, and in particular, Trinitarian articulation against the theologies following Arius, Hilary's De Trinitate remains an important work in understanding the continuing debates over Trinitarian matters in the mid- to late-fourth century.
Read introdutions to Hilary on the Pachomius and NewAdvent web sites.
The De Trinitate is divided into twelve books:
Text from the Nicene and Post-Nicene Fathers, Second Series, vol. 9 (eds. P. Schaff and H. Wace; American Edition, 1899)