Ptolemy III was a ruler of ancient Egypt from 246 to 222 BCE, belonging to the Ptolemaic dynasty. He was the son of Ptolemy II and Arsinoe II, and he is known for his military campaigns and efforts to expand Egypt's influence. His reign is often considered a high point in the Ptolemaic period, marked by prosperity and cultural achievements. During his rule, Ptolemy III initiated the Third Syrian War against the Seleucid Empire, successfully capturing key territories. He also promoted the arts and sciences, supporting institutions like the Library of Alexandria, which became a center of knowledge in the ancient world.