The Band-e Kaisar (Persian: بند قیصر, "Caesar's dam"‎‎), Pol-e Kaisar ("Caesar's bridge"), Bridge of Valerian or Shadirwan was an ancient arch bridge in Shushtar, Iran, and the first in the country to combine it with a dam. Built by a Roman workforce in the 3rd century AD on Sassanid order, it was also the most eastern Roman bridge and Roman dam, lying deep in Persian territory. Its dual-purpose design exerted a profound influence on Iranian civil engineering and was instrumental in developing Sassanid water management techniques.