Arsinoë II was a Ptolemaic queen and co-regent of the Ptolemaic Kingdom of ancient Egypt. She was given the Egyptian title "King of Upper and Lower Egypt", marking her pharaoh as well.
Arsinoe was Queen of Thrace, Anatolia, and Macedonia by marriage to King Lysimachus. She became co-ruler of the Ptolemaic Kingdom upon her marriage to her brother, Pharaoh Ptolemy II Philadelphus.