Atropates
The area of Atropates' kingdom was known to the Greeks as "Media Atropatene" after Atropates.  Then as simply "Atropatene". The Arsacids called it 'Aturpatakan' in Parthian, as did also the Sassanids. Eventually Middle Iranian 'Aturpatakan' became 'Azerbaijan'.  This is where the Republic of Azerbaijan and the Iranian province of Azerbaijan get their name.