The famous EID MAR aureus, which was on loan to the British museum for more than a decade, has come up for auction. (We had a thread on this coin from 2010. See below.) It is estimated to fetch more than US$2 million dollars: https://www.barrons.com/amp/articles/ancient-gold-coin-marking-julius-caesars-assassination-expected-to-fetch-2m-at-zurich-auction-01647368399     Here is an excellent thread on the EID MAR aureus: http://www.thehistoryblog.com/archives/59762