Arsinoe I of Egypt

Arsinoe I (Greek: Αρσινόη Α’, 305 BC-after c. 248 BC) was a Greek Princess who was of Macedonian and Thessalian descent. She was the second daughter and youngest child born to King Lysimachus from his first wife, Nicaea of Macedon. Arsinoe I had two older siblings: a brother called Agathocles and a sister called Eurydice.

Arsinoe's paternal grandfather was Agathocles of Pella, a nobleman who was a contemporary to King Philip II of Macedon who reigned 359-336 BC, while her maternal grandfather was the powerful Regent Antipater. Arsinoe I was named in honor of an unnamed grandmother, who may have been the mother of Lysimachus or the mother of Nicaea whose both names of these women are unknown. Little is known of her life prior to her marriage.

Between 289/28 and 281 BC, Arsinoe became the first wife of Ptolemaic Greek Egyptian Pharaoh Ptolemy II Philadelphus, who was also her distant maternal cousin. Arsinoe I married Ptolemy II as part of an alliance between her father and Ptolemy II, against Seleucus I Nicator.

Arsinoe I was, by marriage, Queen of the Ptolemaic Kingdom. Arsinoe I bore Ptolemy II three children; two sons: Ptolemy III Euergetes, Lysimachus of Egypt and a daughter called Berenice. At an unknown date between after 279-274/3 BC, a sister of Ptolemy II called Arsinoe II arrived in Egypt, who was the last wife of Lysimachus and had fled from her half-brother-husband Ptolemy Keraunos. Probably at the instigation of Arsinoe II, charges of conspiring to assassinate Ptolemy II were soon brought against Arsinoe I.

...
Wikipedia