The Old Kingdom is the period in the third millennium BC when Egypt attained its first continuous peak of civilisational complexity and achievement ( the first of three so-called `` Kingdom '' periods which mark the high points of civilization in the Nile Valley ) , spanning the period when Egypt was ruled by the Third Dynasty through the Sixth Dynasty ( 2686 -- 2181 BC ) .
This was the first of three so-called `` Kingdom '' periods which mark the high points of civilization in the Nile Valley . It began when Egypt was ruled by the Third Dynasty through the Sixth Dynasty ( 2686 -- 2181 BC ) .