Иоанн Лествичник
Scholars have acknowledged his great influence on later Byzantine saints such as Maximos the Confessor, John Climacus, Symeon the New Theologian, and in general the Hesychast movement of the 14th century. He has also had great influence in the West via the work, "On the Contemplative Life" ("De vita contemplativa") of Julian Pomerius (†498).