Answer:
Osman Gazi, or Osman I, was the founder of the Ottoman Empire.
Step-by-step explanation:
In 1299, a beylik leader by the name of Osman Gazi founded the Ottoman Beylik, or "Osmanli Beyligi". In Turkish, Osmanli means Ottomans, which is a word taken from the Greeks of Constantinople (at the time) and used in the English (Othman --> Ottoman). The Ottoman Beylik would grow slowly but would eventually grow to great sizes under Mehmet the Conqueror, Selim the Grim, and Suleyman the Magnificent.