Archaeological findings and excavations of Qazvin plain approve the existence of settled societies (permanent-residence) and agriculture as well as show that its inhabitants had enjoyed primary industries and social order in the 7th millennium B.C. All of the residential quarters, temples, industrial workshops, ornamental objects, statues, and warehouses of grains etc. found in Qazvin show the civilization of the people of this land in thousands of years ago.

In the old writings of Europeans, Qazvin had been called “Arsas” or “Arsasia” and was named “Ragia” in the Greek writings as well.

The process of urbanization and development of housing in Qazvin after the spread of Islam over the city in 644 A.D. was so intensified that after a while the city was named as Babol Janat or the gate of paradise.

The extent of Qazvin in 867 A.D. can be understood from a narration of The Selected History (Tarikh Gozideh) which says that after carrying out the fortifications by Mousa Ibn Bougha, the city consisted of 206 towers and 7 gates.

Selecting Alamout as the headquarter for Ismailian Nazari and its subsequent cultural, political, and military challenges made Qazvin the focus of many important events of the country for about 200 years; accordingly the city had witnessed many massive military invasions and their devastating effects all the time.
At the time of Mogul invasion, the extent of the city was so vast that, according to Mostowfi‟s narration in Zafar Nameh, more than one million people had been living there. Qazvin regained its prosperity after a short period of recession in Ilkhanid era and according to tourists in Teimourid era, it had been the most cultivated and largest city after Samarqand in Iran.

Selecting Qazvin as the Safavid Capital in the 16th century A.D. in addition to magnifying the importance of the city brought about an excellent period of urban development which is observable in the writings of western ambassadors and merchants.

Even transferring capital from Qazvin to Isfahan in the 17th century A.D. did not make city fall into oblivion and until the end of Afsharian era we observe that a lot of magnificent edifices were made all over the city from which the splendid Naderi Veranda is to be named.

Throughout the Qajar era Qazvin was a self-ruled region connected to the Capital and in spite of its slight recession in economy and culture at that time, it was one of the active and flourishing centers of the country.

The heroic resistances of the people of this part of the country against the invasion of the savage and murderous Mogul troops as well as against devastating raid of Teimour, especially imposing the first defeat on Afghan invaders in Qazvin after the fall of Isfahan, demonstrate the undeniable role of the people of Qazvin in the history of the country. Public participation of people in anti-despotic constitutional movements is the beginning of a new period of the contemporary history in the country which continued till The Islamic Revolution happened in 1978 A.D.

Following the repeated attacks of Ottoman to Tabriz and insecurity in capital, The Safavid King decided to move the capital to Qazvin which they had spent the recreation times in its countryside before. So the capital finally moved to Qazvin by command of shah Tahmasb, the second king of Safavid, in 1544 A.D, and became the second Capital of Safavid dynasty.

After deciding to move the capital from Tabriz to Qazvin, Shah Tahmasb bought some lands known as Zangi Abad and commended to construct a magnificent royal court there.

In its glory times, the royal court had 23 collections of palaces and gardens that were surrounded by 7 gates.

Years later, after fall of Safavid, a commander of Qazvin started to abandon different parts of the royal court to the offices and private sector, so it caused loss of many important monuments including most of palaces and gates.

Now the relict square is generally 8.5 hectares and is located in central part of the city.
Chehel Sotoun palace and Ali Qapu entrance are the most important remained monuments inside it.
Beside them, some monuments from Qajarid or Pahlavid are also noticeable. For example the oldest hotel with European architecture style in Iran, Grand Hotel, the mausoleum of four Jewish Prophets and Omid school, the first modern school in Qazvin, are the samples of relict heritages.

The ambassador of the Roman empire, Georg Tectander von der Jabel in Shah Abbas court stated: Qazvin can be comperd with the city Brescello. This city has no fences.

On October 26th, Robert Shirley and I set out, and after 5 days we reached the first city in Iran, which was on this route, Qazvin. It was so peaceful there that there was no need for any fences or fortresses.
Jean Baptiste Travernier

French merchant and traveler (1605-1689)

There is no walls or fortification around the city and most of it is consists of Gardens.
The ambassador of Spain, Garcia de Silva Figuera (1550-1624) was in the court of Shah Abbas Safavi and he stated: Qazvin is such a big and important city that the Iranian Kings made it the capital, and their residence.
Jean Chardin (1643-1713) was a French tourist who said: Qazvin is a big and beautiful city in a wide plain with hot summer days and cool, and occasionally cold nights…

There are tons of inexpensive eatables, and the villages around it are full of clean water and fertile lands. All sorts of foods are grown in their huge and plenteous gardens, which the gardeners will take to the city. The best royal grapes, each bright and clear are produced in Qazvin.

This kind of grape is used to produce raisin, which in turn will be used to make the best and the most tasteful of Wines within the four corners of the world. These Vines are able to withstand the extreme heat of the sun without any water. And also the trees bear fine Pistachio.

British adventurer and traveler Robert Shirley (1581-1628)

He considered royal palace very impressive and said “ when you found ourselves in the royal palace everything was great, the port was nicely decorated with precious stones as I have never seen anything like it anywhere in the world. We went up 7 stairs and arrived to this port which was six yards wide and made of firm stones.

Adam Olearius (1603-1671)

From the Secretary ambassador of Germany to the king of Iran

Also in the roofed Bazaars of the city, trading is actively in progress and all the necessary goods are available with decent and mostly cheap prices