Well, I learned something last night. =) I was researching what candies were available in the Colonial era and come across this fun site that gave me exactly the information I needed. I clicked onto the marshmallow link and proceeded to be awed, LOL.
So apparently, marshmallows originally came from--get this--a plant called the mallow. That grew in marshes. Logical, but something I never knew. But as far back as ancient Egyptian days, folks would take the roots of the marsh mallow, boil them down, squish 'em up, and then combine them with honey. This confection was so prized that it was reserved for royalty and offerings to the gods.
The mallow plant had medicinal uses, primarily for treating wounds and alleviating hunger. Common in Europe, they began mixing the gummy root matter with white sugar and an egg white for fluff, boiling it until it thickened, and then letting it cool into something that was both medicine and confection.
In the 1850s, gum arabic began replacing the marsh mallow root, and the modern treat emerged. Featuring simple ingredients like the gum, cornstarch, egg white, and sugar, it has been largely unchanged for the last hundred fifty years. At that point they were made by hand in confectioner's shops.
By the early 1900s they were being mass-produced and were considered a treat for children., sold as penny candy Today, of course, they're in everything from sweet potato recipes to Jell-O salads to campfire favorites. =)
So there you go--a brief history of a treat we all probably take for granted, but which has its roots (pun intended) in ancient history. Who knew? Marshmallows from a marsh. Go figure. ;-)