Khosrau I
Starting with Peroz I (), the shahs of the Sassanid Empire built a line of stone fortifications to protect the vulnerable frontier along the Caspian shore; when completed under Khosrau I (), this stretched over from the eastern foothills of the Caucasus to the Caspian Sea. The fortress of Derbent was the strategically crucial centre-point of this fortification complex, as evoked by its Persian name "Dar-band", "Knot of the Gates."