>Hey there you philatelist you!

Hey Doug, that's me all right. Today I'm playing numismatist - though properly put, and compared to my philatelic knowledge, you can safely call me an ordinary coin collector <g>

I did some research last night on "In God We Trust" from my Yeoman's red book and my coin collection. I have a pretty good "type" collection (one of every type of coin, and it includes each time a design change (like a motto) in a denomination was made, from 1800 on) going from 1/2-cent up to $5 gold, in addition to my other regular collection.

The insignia first appeared in 1864 on the 2-cent coins, and became standard on coins from quarters-on-up in 1866. So, clearly it was the Civil War and that period of nationalism from the Civil War that began it. The 2-cent coin actually died shortly after the insignia appeared, ironically, not very popular with users.

Smaller denominations generally didn't get the insignia until after 1900, at least partly because there wasn't deemed enough space, and back then "Liberty" was given preference over what space there was for extra wording beside Unites States and the denomination, and sometimes E Pluribus Unum. Coins all had Liberty since their inception in the 1790s. 20-cent coins, although issued in the 1870s, never got the insignia, they were the border denomination, I guess. They also died soon, anyway, and whoever thought them up was a laughingstock, as they looked almost exactly like quarters.

I didn't find any mandate ever made from Congress or White House at all, so I think the insignia is still done voluntarily when a new coin design is approved, and now it's tradition like Liberty and E Pluribus Unum.

Pennies got the insignia 1909 (there was perhaps enough nationalism just then), nickels in 1938, dimes in 1916, the higher ones all got it in 1866 (though it's very fine print and hard to see on smaller gold coins, it's in a tiny ribbon on the reverse. But Buffalo nickels are a strange exception, they began minting in 1913 but never got the insignia. One might conclude that in 1913 there was an environment of much less nationalism, as the US was trying to stay out of world affairs right then as the War in Europe was unfolding. Isolationism was the general feeling, and perhaps it showed up in that way.

But by 1916, the US was aware they were drawn into the Great War, and high nationalism once again became the norm - so Mercury dimes got it. Just some historical-context guesswork on my part on these coins, if anyone knows more concretely, please speak up.