Two of my favorites on his list are Roger Bacon and Robert Grosseteste.

FORBES: Rick Santorum and the 13th Century

In 1267, legendary English scientist Roger Bacon published a recipe for gunpowder, and by the late 1300s, handheld, muzzle-loading pistols were common in Europe.

FORBES: No. 7 The Rifle

Until then, the Catholic Church branded as heretics scientific investigators who, like the 13th-century English friar Roger Bacon, calculated that the current calendar year was over-running the solar year by a whole day every 125 years.

ECONOMIST: Late for the date

On the other hand, the text could just be gibberish and the book which may have been passed off to Emperor Rudolph as the work of Roger Bacon, a 13th-century natural philosopher, in exchange for the princely sum of 600 gold ducats a grand hoax.

ECONOMIST: A possible explanation for the world's most enigmatic book