Amenemhat III .

Head of a statue of King Amenemhat III 
The Metropolitan Museum.

The third was one of the sixth pharaohs of the Twelfth Dynasty.  Rule from 1860 BC.  Until 1814 BC, it is considered the greatest Pharaohs of the Central State.  He may have co-ruled with his father, Sisostris III, for 20 years before he rose to power.  He built the first pyramid in Dahshur, whose construction was marred by structural problems that called for leaving the project before its completion.