Augustine of Hippo (354-430) is viewed as one of the most important Church Fathers in the West.

Although raised as a Christian, Augustine left the church to follow Manichaeism (a major Gnostic religion that was founded by the Iranian prophet Mani).
After his conversion to Christianity and his baptism in 387, Augustine developed his own approach to philosophy and theology.

In The City of God , begun around 413, we find the clearest exposition of the matureAugustine's definition and understanding of the relationship between emotion and intellect.Essentially, the mature Augustine differentiates between passions ( passiones) and affections ( affectus, motus ), wherein passions are the more base and corrupt desires of humanity that flowfrom one's fallen nature. Affections then, are those feelings that operate within the will and arethus attached to reason and the mind.

Emotion was joined to reason, though, through Augustine's Trinitarian concept of human nature,described in The Trinity, completed around 419. Here Augustine rejects "the Platonic view thatlearning is recollection," and instead describes the immaterial aspects of the mind, namely"memory," "understanding," and "will," in Trinitarian terms. That is, Augustine believeshumanity created in the image of God ( imago Dei ) is a reference not merely to the one God, butmore precisely to the one God in three Persons. In fact, advancing this Trinitarian understandingof the imago Dei was one of Augustine's primary aims in his writings on The Trinity. 49

Within "The Trinity" and "City of God" we have the full expression of Augustine's balancedview of intellect and emotion. He came to believe that religious beliefs must be "affectivelyexperienced as well as cognitively grasped."

His On the Trinity, in which he developed what has become known as the 'psychological analogy' of the Trinity, is also among his masterpieces, and arguably one of the greatest theological works of all time.

Links:
Augustine of Hippo's Trinitarian Imago Dei for Balancing Intellect and Emotion in the Life of Faith | Jerry Ireland - Academia.edu
Augustine of Hippo - Wikipedia, the free encyclopedia