Tus , also spelled as Tous, Toos or Tūs, is an ancient city in Razavi Khorasan Province in Iran near Mashhad. To the ancient Greeks, it was known as Susia . It was also known as Tusa. Tus was divided into four cities, Tabran, Radakan, Noan and Teroid. The whole area which today is only called Tus was the largest city in the whole area in the fifth century.