Short answers, pulled from the story.
The Curmsun Disc is a convex-concave gold disc that first gained scholarly attention in 2014. Its design carries features resembling Byzantine coins and seals, and a majority of scholars who have studied it question its dating, its provenance, or believe it to be a forgery.
The Curmsun Disc was reportedly found as part of a Viking Age hoard discovered in 1841, inside the cellar crypt of a ruined church in Groß Weckow, now called Wiejkowo, in what was then Pomerania, Prussia. The site is now part of Gmina Wolin, Poland, near where the Viking stronghold of Jomsborg once stood.
The obverse of the Curmsun Disc reads +ARALD CVRMSVN+ REX AD TANER+SCON+JVMN+CIV ALDIN+. Translated, it reads Harald Gormson king of Danes, Scania, Jomsborg, town (or bishopric) Aldinburg, meaning Oldenburg in Holstein.
Michał Sielski's 11-year-old great-granddaughter showed the Curmsun Disc to her history teacher in 2014, after the disc had been kept in a box with old buttons since 1945. The find was reported in the press on the 5th of December 2014.
A majority of scholars who have studied the Curmsun Disc have questioned its dating or provenance, or have called it a forgery. Numismatist Mateusz Bogucki believes it is a counterfeit likely made by antiquity enthusiasts in the 18th or 19th century, and archaeologist Wojciech Filipowiak has said that as of 2022 no publication had proven it genuine.
The Curmsun Disc has an insured value of US$3.5 million. That valuation was performed by gemologist Jonny Westling, appointed by the Swedish Chamber of Commerce in Stockholm and Lloyd's/Brookfield Underwriting.