Alexandrian Boubasteion, the temple of the syncretic Greek-Egyptian goddess Boubastis (Bastet-Artemis -the patroness of pregnant women, childbirth and small children), was discovered in 2009-2010. One of the most interesting finds made on the territory of the temple are the Greek and Egyptian foundation plaques. The founder of the temple, indicated in the texts of the plaques, was the Ptolemaic queen, Berenice II, the wife of Ptolemy III . In particular, this is indicated by the naming of the queen as "daughter of Re", the identification of King Ptolemy as her "brother and husband" and accompanying the name of the latter with the wish "living forever, beloved of Ptah".The researchers came to the right conclusion that Boubasteion was founded in 244-243 BC. This can be deducted from the texts of the plaques which mention that Ptolemy and Berenice had more than one child, but don't mention the cult epiclesis of the royal couple, "gods-Euergetes". I believe that Berenice founded Boubasteion directly on the occasion of the birth of the heir to the Alexandrian throne -the future Ptolemy IV.I agree with Ch. Bennett and B. van Oppen de Ruiter that above-mentioned prince was the second child in the family and was born in the middle of 244 BC. The additional arguments in favor of this assumption are: the absence of mentioning birth of the prince in the poem "Lock of Berenice" by Callimachus, and the journey of the royal family to the island Philae (dated 244/243 BC), which was an all-Egyptian presentation of the future pharaoh. At the same time, the foundation of the Alexandrian Boubasteion by Berenice and the foundation of the chapel of Isis and Harpocrates on Philae by the royal family probably acted as a pair of expressions of gratitude to the gods for the birth of the son.The final touch in the dating of the Berenice's Boubasteion is Bastet-festivals -Boubasteia that were conducted in Egypt and happened on the 4-8 th August in 244 BC. This time period perfectly fits for the foundation of the Alexandrian temple of the cat goddess.