Evagrius Ponticus (Greek: Εὐάγριος ὁ Ποντικός, "Evagrius of Pontus"), also called Evagrius the Solitary (345–399 AD), was a Christian monk and ascetic. One of the most influential theologians in the late fourth-century church, he was well known as a thinker, polished speaker, and gifted writer. He left a promising ecclesiastical career in Constantinople and traveled to Jerusalem, where in 383 he became a monk at the monastery of Rufinus and Melania the Elder. He then went to Egypt and spent the remaining years of his life in Nitria and Kellia, marked by years of asceticism and writing. He was a disciple of several influential contemporary church leaders, including Basil of Caesarea, Gregory of Nazianzus, and Macarius of Egypt. He was a teacher of others, including John Cassian and Palladius.
Read about Evagrius Ponticus in Wikipedia