In 1902, rumors started to circulate in Egypt about a hoard of Roman gold that had been uncovered by peasants. Later that year some Syrian antiquities dealers arrived in Paris, accompanied by an "Oriental woman" not named in any source I can find. They offered an impressive collection for sale: more than 600 Roman aurei (gold coins), 18 gold bars and 20 gold medallions, which they said came from the Delta town of Abukir. Based on the dates of the coins, the hoard was buried in the second half of the third century AD. Because of the dubious character of the sellers and the unusual nature of the finds, Parisian dealers decided the medallions were fake, and would not buy them. However, a German scholar recognized them as genuine and bought four for the museum of Berlin, where they remain. The rest went back to Egypt and were then dispersed through various deals. Eleven are in Portugal, and three ended up at the Walters Museum in Baltimore.
The medallion images are all on the theme of Alexander the Great, and one bears an inscription relating it to the Olympic Games. Museum guides say that these medals were given to Olympic victors, but classical scholars disagree for technical reasons.
So the medallions represent a mystery. Made by the best craftsmen, probably for the imperial household, they no doubt represent an attempt to associate the imperial family with Alexander.