From the Metropolitan Museum:
…The expansive nature of his work is underlined by the fact that Herzfeld is still considered foundational to two different fields of scholarship today. Among historians of Islamic art, Herzfeld is celebrated for his excavation of Samarra, an archaeological site on the Tigris some one hundred kilometers north of Baghdad. […] Herzfeld is equally lauded in the field of ancient Near Eastern art and archaeology. Most notably, he conducted excavations at the Achaeminid sites of Pasargadae and Persepolis, both located in Iran. Herzfeld's excavations at Persepolis were undertaken from 1930–34 as part of a project administered by the Oriental Institute at the University of Chicago. Among the most significant findings of the Persepolis campaign was the discovery of the Eastern Stairway of the Apadana (columned audience hall) of Darius and Xerxes, which included bas-relief friezes depicting a procession of delegates bringing tribute to the Achaeminid ruler.