Qazvin, or Ghazvin is the largest city and capital of the Province of Qazvin in Iran. Located in 150 km northwest of Tehran, in the Qazvin Province, it is at an altitude of about 1,800 m above sea level. The climate is cold but dry, due to its position south of the rugged Alborz range. At the 2011 census, its population was 381,598.
The city was a former capital of the Persian Empire under Safavids. Archaeological findings in the Qazvin plain reveal urban agricultural settlements for at least nine millennia. It is thought to have been founded by Shapur II, King of Persia in 250 CE, under the name Shad Shahpur, when he built a fortification there to control regional tensions.
Qazvin has sometimes been of central importance at important moments of Iranian history. Captured by invading Arabs (644 AD) and destroyed by Hulagu Khan (13th century), Shah Tahmasp (1524–1576) made Qazvin the capital of the Safavid empire (founded in 1501 AD), a status that Qazvin retained for half a century.
Qazvin contains several archaeological excavations. And in the middle of the city lie the ruins of Meimoon Ghal'eh, one of several Sassanid edifices in the area.
Qazvin contains few buildings from the Safavid era, dating to the period in which it was capital of Persia. Perhaps the most famous of the surviving edifices is the Chehelsotoon (Kolah Farangi) mansion, today a museum in central Qazvin.
After Islam, the popularity of mystics, as well as the prominence of tradition (Hadis), religious jurisprudence, and philosophy in Qazvin, led to the emergence of many mosques and religious schools.
Qazvin is famous for its Baklava, carpet patterns, poets, political newspaper and Pahlavi(Middle Persian) influence on its accent.