[quote=Guilty Spark]
The Old Kingdom's collapse is open to discussion, I was aiming for 1,000 years ago but it could be more (not less). Oragos rose to power around 450 years ago (on this timeline), and it's decline occurred 100 years ago.
[/quote]

Dynasty's tend to occur with major changes in the political situation. If it's all right with you I'd have the Fifth dynasty past the 500 mark.