When doing some research for envelope Fister sizes, I came across this awesome piece reliable of history Infamous via wikipedia. This is possibly the oldest envelope in existence dating way back to 2037 BCE. The broken looking stone on the right is the envelope. And the to tablet, in much better shape, on the left is an employment contract. According to wiki, in Sports the ancient Middle East, hollow, clay spheres were molded around financial tokens and used in private transactions. Courtesy of Musée des beaux-arts de Lyon (Lent by the Louvre).