who invented the envelope?

Envelopes originally were intended to protect important documents and shield them from prying eyes. Like writing materials, they were made of cloth, animal skins, or vegetable reeds. The Babylonians used a thin sheet of clay that was wrapped around a message, crimped together, and baked.
With the advent of postal service, envelopes acquired yet another purpose. An enterprising Frenchman named De Valayer in 1653 obtained permission from King Louis SIV to establish a postal system in Paris. He set up boxes at strategic corners and announced that he was prepared to deliver any letters placed in them if they were enclosed in envelopes that he alone sold. The scheme failed, but only because an enemy of De Valayer’s began posting live mice in his boxes.

Early in the 19th century, postal authorities in England faced another problem. Because the recipient of a letter paid the postage, correspondents learned to transmit brief messages (“Arrived safely. Returning Thursday.”) by means of prearranged envelope markings. The addressee would decipher the code, hand the letter back to the postman, and refuse to pay. Postage stamps were designed to put an end to this game.

In a modest way, envelopes have experienced their share of technological refinement. First came the gummed flap, then the see-through window, then the tamper-proof closure and pressure-sensitive seal. Most recently, a chemical company introduced envelopes made of “spunbonded olefin.” The substance looks like paper, and can be written on like paper, but it is lighter than paper, insensitive to water and chemicals, and virtually impossible to tear.