Nubia covers an area stretching along the Nile valley from the sixth cataract in the south to the first cataract in the north, which marks the southern border of pharaonic Egypt. The first distinct culture, designated A-Group by modern historians, develops in Lower Nubia between 3700 and 2800 B.C. The A-Group people are eventually ruled by a series of powerful kings and later driven out by the Egyptians.