According to Enrico Fabri, of the Società Arte e Scienza, Milan, carbon-14 tests and handwriting analysis have confirmed Leonardo Da Vinci to have been the author of a set of four folio-sized pages, discovered in 1982, containing a number of those wonderful inventions for which Leonardo is famous.
The papers date to 1510 (+/- 2 years), when Leonardo was attending the court of Louis XII (1462-1515), then based in Milan.
Aside from being known as the "Father of the People," Louis XII had a modern and relaxed aspect and was among the first to take up smoking. However, he tended to smoke "hot," which accounts for Leonardo's unique design, in which the carved panes allow faster cooling, as well as a comfortable grip.
Realization of Leonardo Da Vinci's masterpiece