Few museums of Asian art boast a collection of Near Eastern Art as rich as that of the Freer and Sackler galleries in Washington, DC. The objects in this collection span several thousand years, from 5,000 B.C.E. to the advent of Islam in 651. These are from Sasanian period (224–651 A.D.) in Iran. Also, if you are in New York, don't miss Asia Society's current exhibit, “Glass, Gilding, and Grand Design: Art of Sasanian Iran“.