Johannes Scotus Eriugena was an Irish philosopher, theologian, and poet who lived in the 9th century. He is known for his work in translating and interpreting the writings of the early Christian Church Fathers, as well as for his own original philosophical and theological contributions. Eriugena's most famous work is "Periphyseon," also known as "De divisione naturae," in which he explores the nature of God, creation, and the relationship between the divine and the material world. He is considered one of the most important figures in the development of Christian Neoplatonism and is often regarded as one of the greatest thinkers of the early medieval period.