Himerius was a Greek teacher and orator of the 4th century CE, a later figure in the tradition known as the Second Sophistic. He was born in Prusa in Asia Minor but spent much of his career in Athens, where he led a highly successful school of rhetoric. His skill attracted students from across the Roman world, including notable future Christian figures. The emperor Julian, who promoted traditional Greek culture, invited Himerius to Constantinople around 362 CE for an official role. After Julian's death, Himerius returned to Athens to teach until his own death, which is estimated to be around 386 CE.

His surviving works consist primarily of orations and rhetorical exercises. While he is known to have delivered many speeches, only about two dozen complete orations and excerpts from several dozen others remain. These include ceremonial addresses, private speeches, and practiced declamations on historical and mythological themes. His style was notably elaborate and poetic, filled with allusions to classical literature.

According to modern scholars, Himerius is significant for illustrating the state of Greek education and rhetoric in late antiquity. His career bridges the pagan cultural revival under Emperor Julian and the increasingly Christian empire that followed. As a teacher, he helped transmit the traditions of Greek learning to a generation that included future Christian leaders, highlighting the complex relationship between Hellenism and early Christianity. His works provide valuable insight into the intellectual and social life of his time.