The Sassanids ruled Persia from the 3rd through the 7th Century A.D. Thier Empire comprised much of what we traditionally think of as Persia, including parts of Egypt. Thier primary rivals for dominating the world of the Mediteranean were the Romans. Because of thier relationship with Egypt, we do have some extent garments available for study.
Shirt Sassanid Period, found in Egypt
Sassanid Coat, Early 7th Cent., picture provided to me by Jennifer Davis
Sassanid Riding Coat with Construction Diagrams Found in Antinoé Egypt, located in Museum für Byzantinische Kunst Berlin
Metal Plate showing Shapir I
Stucco showing Shapir II
The following resources are not located on my website:
Sassanid Clothing Article by Jahanara Vivana