|A 1381 letter patent for transfer of property, with king's seal.|
According to American classical scholar Charles Anthon (1797-1867), the first known patent was granted in 500BCE in Sybaris in southern Italy. He tells us:
encouragement was held out to all who should discover any new refinement in luxury, the profits arising from which were secured to the inventor by patent for the space of a year. [Classical Dictionary, 1841]In medieval Europe, the phrase "letter(s) patent" came into use to distinguish the decree from a "charter." The charter generally declared a law or right that was granted to a family or institution in perpetuity. The letter(s) patent declared a right to an individual and was of a finite duration. The letter patent was sent open, so that all could see it and be aware of the legal action it portended; this was distinct from "letters close," a private letter sent from a royal personage or from the chancery.
Letters patent were very specific, and the king was willing to grant them because he usually saw benefit from them. So, in 1331, Edward III grants a patent to John Kempe, a Flemish weaver, as an inducement for skilled foreign labor to settle in England and instruct the English in advanced textile-related techniques. This, of course, would greatly benefit the economy of England in the future. Note that this was not a patent (in the current sense) for protection on an invention; it was a letter of "protection" to allow a foreign worker to ply his trade without threat from rival local workers.
The idea of a "patent" in the modern sense—the right to use your own invention in public without fear that someone would copy it and benefit from it—comes a little later. In 1421, Florentine architect Filippo Brunelleschi (1377-1446) received a three-year patent granting him exclusivity on his invention: a barge with a hoisting device to transport slabs of marble. A generation later, in 1449, Henry VI of England granted what is considered the first true English patent to John of Utynam for his method of making colored glass. John, a Flanders native like Kempe, got 20 years of exclusive benefit for his methods; his first commission was to make windows for Eton College.
In 1474, Venice declared that any new inventions must be presented to the public so that the inventor could be granted the right to prevent their theft by others. This is considered the beginning of the modern approach to patents.