The Ptolemaic Dynasty was a Hellenistic royal family that ruled Egypt from 305 BC to 30 BC, following the death of Alexander the Great. Established by Ptolemy I Soter, a companion of Alexander, this dynasty blended Greek and Egyptian cultures, influencing politics, art, and science during its reign. The dynasty is notable for its significant contributions to both Greek politics and culture, as well as advancements in scientific and technological fields.