Answer: Because of the weak horse riding skills.
The Ottoman Empire was one of the longest in history, lasting from 1299 to 1923.
The founder was known as Osman I, or Othman. Osman belonged to the Seljuk group, Turkish nomads who converted to Islam and formed an empire that dominated Central Asia in the twelfth and thirteenth centuries. In 1299 Osman declared his jurisdiction in Anatolia, then linked to the Seljuk Empire, independent of it. From that year was founded the Turkish-Ottoman sultanate.