Ptolemy III Euergetes was a ruler of the Ptolemaic Kingdom in ancient Egypt, reigning from 246 to 222 BCE. He was the son of Ptolemy II Philadelphus and Arsinoe II, and is known for his military campaigns, particularly against the Seleucid Empire. His reign marked a period of prosperity and cultural development in Egypt. Ptolemy III is also recognized for his contributions to the arts and sciences. He established the Library of Alexandria as a center of learning and supported various cultural projects. His reign is often seen as a high point in the history of the Ptolemaic dynasty.