Poimen (reportedly from 340 to 450) was an Egyptian monk

Monk

A monk is a person who practices religious asceticism, living either alone or with any number of monks, while always maintaining some degree of physical separation from those not sharing the same purpose...

 and ascetic. He was noted for strict fasting and giving counsels. He is considered a saint

Saint

A saint is a holy person. In various religions, saints are people who are believed to have exceptional holiness.In Christian usage, "saint" refers to any believer who is "in Christ", and in whom Christ dwells, whether in heaven or in earth...

 in Eastern Christianity. His feast day is August 27 in Julian calendar

Julian calendar

The Julian calendar began in 45 BC as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year .The Julian calendar has a regular year of 365 days divided into 12 months...

(September 9 in Gregorian calendar)

Biography

Venerable Poimen was born around 340 or 350 AD in one of the Egyptian cities. The exact place are unknown. He was one of six brothers: John, Jacob, Job, Joseph, Sonosyos, and Abraham. They all agreed to become monks, and they dwelt in a remote place, becoming ascetics and hermits.