Libanius of Antioch (A.D. 314-393) stands out as a fundamental source for the history of the Greek East in the fourth century. An eloquent exponent of Greek culture and of the traditional style of Greek civic life, Libanius consistently advocated humanity and tolerance in the face of the religious extremism and social oppression that too often characterized the era in which he lived. During a teaching career that spanned more than five decades, he developed a vast network of connections: some 700 people, including many of the key players of the age, are known through his vast letter collection, the largest to survive from antiquity.This volume offers translations of 183 letters, addressed to a wide range of people, from family members to old schoolmates and pupils, from provincial governors to the most important officials of the imperial court. Drawn from the 1, 269 letters written between 355 and 365, these letters play an important role in making the age of Constantius II and Julian the Apostate the most richly documented period of the ancient world.