A quick review of my genealogy matched what he told me, and with more information, including his full name, I googled more. Yes, indeed, he is a very well-known coin collector/dealer, and soon I'm quite interested in knowing more and could I post his two images.
An immediate response came, and since it was interesting, I've decided to share it. "The coin is dated 1696 - You can just about see the date to the left on the reverse (the engraving side above the ‘R’) the crown on the shield splits it. Yes, the coin had been in circulation for nearly a hundred years – which is why it is quite a worn piece (Not uncommon – I can remember Victorian coins in my change as a schoolboy in the 1960s). Not old by English standards. Our first coins were issued in around 40 BC. This coin of William III is the sort of coin that circulated in America before you revolted – and of course this English king named Williamsburg. The first US coins were only issued in the 1790s." "The reason there is an anchor on it is because Robinson Elsdale (senior) was in the navy and a sea captain. The coin was obviously engraved for him (senior) as a keepsake for the birth of his son of the same name – and he died a few months after (That really threw me having a Robinson Elsdale dying in 1783 and a Robinson Elsdale being born in 1783 !!!)"
"In the late 18th. century it was all the fashion to engrave coins as keepsakes and love tokens. Most commonly to give to one’s sweetheart especially by sailors who might spend months away from their love – but also as memento mori and birth tokens. They are tremendously popular at the moment because of the ancestry bit, unfortunately whereas thirty years ago they were very cheap to buy, now they are not."
All of us who blog or have our ancestry online are used to having people write us about all kinds of things. Anything from wanting information, giving information, asking miscellaneous questions, and now, I have a coin dealer giving me some information that ties into my genealogy tree. My fourth great-grand aunt was married to the father whose name is on this coin, and she was the mother of the son who probably received this coin.