Charlemagne, meaning Charles the Great, was King of the Franks from 768 and Emperor of the Romans (Imperator Romanorum) from 800 to his death in 814. He expanded the Frankish kingdom into an empire that incorporated much of Western and Cent...

Mehmed II (1432-1481), nicknamed the conqueror, was the sultan of the Ottoman Empire a short time in 1444 to 1446, and from 1451 to 1481. Mehmed II brought an end to the Byzantine Empire by capturing Constantinople in 1453 (during the well-...

John Harrison was a self-educated English carpenter and clockmaker. He invented the marine chronometer, a long-sought after device for solving the problem of establishing the East-West position or longitude of a ship at sea, thus revolution...

Wilhelm Conrad Röntgen was a German physicist, of the University of Würzburg, who, on November 8, 1895, produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgen Rays. Röntgen's discovery of x-ra...