@PotomacBobThis is a difference between Robin Hood's time and Robin Hood's time.
The book came out in 1883.
The story is sent much earlier than most Robin Hood tales. Most are 13th or 14th century, but The Merry Adventures of Robin Hood is set between 1189 and 1199. We know that because, in the story, Robin and his men are pardoned by King Richard the Lionheart, whose reign was 1189 to 1199.
So, for the author, perhaps $40k.
But, for the characters in the story, that's likely far more than $2.8 million.
Which begs the question: what was Pyle thinking of? My guess is the $40k figure or thereabouts. He was probably giving a figure that would make sense to contemporaries as 'a lot of money', not 'enormously life-changing wealth'.
But, with the story set in 1189-1199, it's not even clear what the pound was. The first pound coins don't appear until nearly 300 years later.
One other way to look at it is that one pound (unit of weight) of the silver coins in 980 would buy you 15 head of cattle. But coinage got much worse, so badly that many makers of money were severely punished for debased coins in 1124. That likely improved matters :) but might not have gotten the 'pound' back to the 980 value.
If you toss out a rough guess of 10 head of cattle, in today's money that's $30,000. 200 is, then, $6,000,000, and we're back to life-changing sums of money.
Which means, again, the author is probably using roughly 1883 pounds, which is a mistake on the author's part but makes the $40k guess more likely to be right than wrong. It could be nearly anything, though.
Even writing in 1980s prices (which I do, since that's where my story is set) is a pain in the butt sometimes. It would be far worse trying to write in real-world prices from hundreds of years ago!