Northwest Iran has been a very important archaeological site for Iranian history. At Nader Tappe, in the province of Ardabil, mud houses dating back to 3000BCE have been uncovered. Architectural remains have also been discovered at the site of Yeri. In addition, 5000 steles depicting human faces without mouths have been found near Yeri. Archaeological analysis of the ancient site of Gilvan, dating to around 1000BCE, has provided evidence regarding the development of the Iron Age in Iran. Previously, it had been assumed that the Iron Age started outside Iran and was imported. However, new evidence from Gilvan shows that the Iron Age of Iran may well have started inside Iran.
The kingdom of Mannae was a state in Northwest Iran that predated the Median empire, really developing around 850BCE. The Mannaean homeland was centered in the region south of lake Urmia; at its greatest extent the Mannaeans stretched as far north as the Kura River. As the Mannaeans developed, to the West in the greater Armenia region, the Urartians came into conflict with them. During the war with Urartu, Mannae expanded and reached its strongest under the reign of Iranzu. However, by 716BCE, under Sargon II the Assyrians invaded Mannae and destroyed the kingdom. Most of its cities were looted and salt was plowed into the land. Around 676BCE the Mannaeans revolted against Esarhaddon of Assyria and continued to expand under the following King Asheri. Eventually the Scythian invasion further damaged Mannae and shattered the kingdom. What remain of Mannae was absorbed by the Median Empire.
At Qalaichi Tappe and Rabat Tappe glazed bricks have been uncovered. The bricks have many different motifs and depict a variety of styles. Excavations in Rabat Tappe have lead to the discovery of pottery shards dating back to 3000BCE. More artwork has been found at Qapan Tappe in West Azerbaijan. The region was a Mannaean city; however, inhabitance at the site dates back to 4800BCE. Hasanlu has also turned up many artistic artifacts. Red and black pottery has been uncovered. The black pottery was typically produced through firing the pottery numerous times which created a bery fragile texture to the pottery. Spouted jars and rhytons at Hasanlu resemble artifacts from elsewhere on the Iranian plateau and indicate the influence other regions might have had on the art of the Mannaeans. Assyrian influence is also readily visible. In addition, many samples of metallurgy and ceramic utensils have been found. The Hasanlu region seems to have been abruptly destroyed around 800BCE. The nearby temple was burned to the ground. The perpetrator of this attack is unknown; however, some names on maceheads dating back to the attack have Assyrian names. Excavations have uncovered a number defensive structures such as the fort found in Ziwiyeh in Kurdistan. Some have decorations and may have also served religious purposes.