They have to be big enough to fit on a monarchs head But seriously, I have never seen a categorical definition. Perhaps someone else has. Just think silver dollar sized, in any composition or country, generally a high fraction of an ounce in weight.
There are two definitions. One is, as sakata said, a silver coin about the size of a silver dollar. These can be any of numerous denominations for a wide variety of countries. When you speak about world crowns, this is generally the accepted definition used. There are also specific denominations called crowns, which can be much smaller than a dollar. For example the Austro-Hungarian Corona/Korona/Krone is a crown, but is more closely the size of a US quarter dollar.
A few sources on the internet describe the numismatic use of "crown" to derive from the French gold couronne issued by Phillip VI circa 1339 that had a crown depicted on its obverse. Later, Henry VIII issued the gold "double rose" crown in 1544 valued at 5 shillings. Subsequent large English silver coins of five shillings were also called crowns and the name would be applied to similar size and value silver coins of other nations as silver coins of roughly 38 mm and one ounce in weight became a standard of international exchange. I use "crown" when discussing large silver coins with other world collectors but will say "silver dollar sized coins" when talking to US collectors.
Although a crown in usually silver it does not have to be, as some have implied. It was a denomination in pre-decimal Britain and there was at least one non-silver crown minted. The 1965 Churchill crown comes to mind.
While I agree with what others are saying, I would not say that the coins being referred to when is talking about the large silver coins commonly called crowns are the same thing as the coins whose denomination is stated as being a crown. To me, and I think to many others, they are two entirely different things. There are however some exceptions to that for there are some large silver coins whose denomination was a crown, but they are few and far between as a general rule. In most cases the denomination of a crown was something else entirely different, thaler/taler, ecu, or 8 reales for example.
For anyone who wants to be clear on the history of the English Crown coin: First issued as a Gold coin under Henry VIII from about 1526. First Silver coin under Edward VI in 1551 - the familiar large size and about 1 ounce. Continued in fine silver (0.925) under various monarchs until last issued for general circulation in 1902. Issued as commemorative coin in 0.5 Silver in 1927 to 1936 bar 1935 (Wreath Crowns), in 1935 (GV Jubilee Crown) and in 1937 (GVI coronation Crown). Issued as Commemorative 5 shilling coin in Cupro-nickel 1951 (Festival of Britain), 1953 (EII coronation), 1960 (New York Exhibition) and 1965 (Winston Churchill). Issued as Commemorative 25p coin in cupro-nickel 1972 (Silver Wedding), 1977 (Silver Jubilee), 1980 (Queen Mother 80th) and 1981 (Charles & Diana). Issued as £5 coin commemorative in cupro-nickel in many forms since 1990. Since 1972 there have also been Silver proof versions, and since 1990 Gold proof versions minted for collectors. Having said all that when I think of "World Crowns" they need to be Silver, around 1 Ounce (+/- 20%) and for me to be genuine circulation coins, not modern commemorative or bullion issues.
This is an extremely informative to me. I collect crowns in the lose sense referring to large silver coins about dollar size. I myself questioned the term crown for certain large silver coins compared to others. Specifically roubles and late thalers form German states around 20/18.5g. I have British double florins which are smaller than crowns but still feels like a big silver "crown"
A double florin was four shillings (5 to the pound) and a crown was five shillings (4 to the pound). Those were the official names, not just terms used to describe the coins. As a child I would get a crown as my weekly pocket money, although by then the crown coin was no longer minted for circulated and I actually received two half crowns. The slang term for five shillings (or crown) was a dollar and I assumed it was based on the time when the conversion rate was four dollars to a pound and when a crown coin and a dollar coin were about the same size.
Yes, and there is a lot of overlap in the terms used for these coins. Another reason for the slang use of "dollar" for a five shilling crown is that the Bank of England produced a "dollar" of similar size, dated 1804 and overstruck on captured Spanish 8 reales coins. I believe these actually traded at 4 Shillings and Ninepence - 3 pence short of Five shillings. Also the word "dollar" is linguistically derived from the same root as "Thaler" and all the variations on that word. Maybe there is something fundamental in mankind's psyche that finds the one ounce coin particularly satisfying?!?
Apparently these were unpopular when issued, likely for the reason you have pointed out. Apparently, there was a contemporary verse that summed up the popular reaction: "To make the dollar of Spain For five shillings to pass, Stamp the head of a Fool On the neck of an Ass."
Typically a coin weighing 25 grams or more, but less than 30 grams. If it will fit in a half-dollar 2x2 it isn't a crown, though double-florins, thalers, and roubles still qualify even if under 25 grams. Also has to be silver. Those are the rules for my collection anyway. The Churchill 1965 Crowns in particular do not qualify in my opinion primarily because they are struck in base metal, which to my way of thinking was a bit of an insult to his legacy at the time they were issued. After all, Great Britain was still pre-decimal at the time, the coin was much smaller than any other Crown denomination GB had ever struck, and it totally lacked precious metal. Perhaps it was a deliberate decision to remind everyone of what a horrible Chancellor of the Exchequer he was, even if he later became a great statesmen.
Whilst I agree with most of what you say, the Churchill Crown was exactly the same size as previous Crown coins back to Charles II in the 17th century. Yes, we were still pre-decimal in 1965 but we had given up using silver in our coins in 1947, so it was not unreasonable that we did not put silver into the Churchill crown. It's aim was to be a souvenir for all the people, so keeping the value down to five shillings meant silver would have been out of the question. I would agree it is not a handsome coin and it is ludicrously common still over here!
I stand corrected, it is the same size. Had momentarily confused it with the 1965 Mexican Peso, another hideously poor excuse for a crown, which while containing silver (an entire 20th of an ounce!) is only 34.5mm in diameter.
I prefer the loose definition of crown but I also really, really, really want the crowns in my collection to have some precious metal. Anyway, here's one from the opposite end of the spectrum, i.e. no one would not call this a crown if you could see it in hand to verify the size and/or PCGS cert number.
