For centuries people have buried their valuable for fear of losing them to thieves. People would bury their treasure in their own backyard and forget about it or they move away and never come back leaving the treasure behind. I once buried a jar full of coins in my dad's backyard; I recently dug it up using my Garrett Ace 250 metal detector. It had been about 30 years since I buried that jar. Although the coins aren't really that old or valuable, they sure did bring back a lot of good memories. Of course, there have also been times where people bury a fortune in gold coins or gold artifacts and for some reason they never dig it up.
There is a story of two boys finding treasure somewhere close from where I am, back then there use to be a town that today doesn't exist anymore and its exact location is a mystery. In the church of that town the priest buried a fortune in gold and silver artifacts before being massacred by the Indians. The two boys stumbled upon the cache by accident and because they had heard stories from an old bootlegger about the place being haunted by the murdered priests they got scared and ran away from there without the loot. Many years later when they were grown, the two boys now men went back looking for the gold but could never find not even a trace of the old town.
I think that the reason for burying treasure was so popular back then was to keep it from being stolen and because at a time in our history people did not trust banks with their money, bank were often robbed by outlaws. I remember seeing old pirate movies; I saw these mean ugly looking pirates bury their stolen treasure, so I guess I thought that was a good thing to do so I buried my jar full of coins and simply forgot to dig it up until 30 years later. When ever you have time grabyour favorite metal detector start looking in your own back yard you never know who lived there before you, maybe they buried some valuables and never came back for them. Happy hunting.