Chauhan king Prithviraj III  was defeated in 1192 by the invader  Muhammad Ghori . [4] In 1206,  Qutb-ud-din Aybak , the first ruler of the  Turkic   Slave Dynasty  established the  Delhi Sultanate . Qutb-ud-din started the construction the  Qutub Minar  and  Quwwat-al-Islam  (might of Islam), the earliest extant mosque in