Arsinoe (Greek: Ἀρσινόη) was a city located on the northern extremity of the Sinai Peninsula. Like the nome which contained the city itself, it was named after Arsinoe II, the wife of Ptolemy II Philadelphus.
In around 38 BCE, Ptahmose, a member of the Order of the Ancients, used the city as his base of operations, pillaging the nearby Pyramid of Amenmesse to fund the war efforts of Rome and Egypt on the orders of his superior, Gaius Julius Rufio, who was a member of the Order in his own right.
His actions were later discovered by Gamilat, the leader of the Nabatean rebels and the Hidden One Bayek of Siwa. Together, both of them infiltrated the pyramid in search of Ptahmose, only to end up finding nothing of his whereabouts. Deducing that the Ancient probably operated in the nearby city, Bayek travelled to the city, where he found and assassinated him in a Roman camp.