Simplify the following text for a Grade 11 native English-speaking person.
Original: The semi-mythical king Gilgamesh , according to the chronology presented in the Sumerian king list , ruled Uruk in the 27th century BC .
Simplified: According to the chronology in the Sumerian king list , the semi-mythical king Gilgamesh ruled Uruk in the 27th century BC .