Caravanserais of Iran are divided into three categories.1) Those that were built outside cities 2) Those that were built near the entrance gates of the cities. 3) Those that were built inside cities
If the caravanserais were built inside cities their construction in parts was similar to that of a traditional bazaar, with the exception that it was a separate and independent section. In some caravanserais, just the tradesmen were accepted with people who carried their cargo; in some other, special places were made for big caravans to unload their cargo and the last form were those caravanserais were carts and carriages could enter to unload. Sa’d Al Saltaneh is a mixture of all these caravanserais.
By the time of its construction, Qazvin was a center of Iran’s trade connecting the north-south roads and east-west roads. Europe’s trading with central and far Asia and also Russia, have turned the city to an important trading spot, both for locals and international traders. After the World Wars and with the economic depressions the caravanserai was almost destroyed, in the years that followed only a small part of the construct was still active and later some parts were sold to factories. The whole place was purchased and reconstructed beautifully it now functions as a bazaar.