Simplify the following text for a Grade 10 native English-speaking person.
Original: It is thought that the first known inhabitants of the Durban area arrived from the north around 100,000 BC , according to carbon dating of rock art found in caves in the Drakensberg .
Simplified: Carbon dating of rock art found in caves in the Drakensberg suggests that the first known inhabitants of the Durban area arrived from the north around 100,000 BC .