A large
immigration of Turkish tribes occurred in the 11th century
to the northwestern regions of Iran. These were primarily
Seljuk Turks who conquered lands and installed their
own dynasties. After that the biggest invasions was the
Mongol
invasion in the 13th century. A brutal, and nomadic group,
the Mongols destroyed major cities, and killed almost
all of the people on their way. The two most important
cities
Ray, and Tus were also ruined at the hands of the Mongols.
During much of their rule, there was no economic, or
cultural growth for the country. The Mongol rulers were
original
Buddhists
and as such did not believe in Islam. Through this a
resistance force, the Sufi order of brotherhoods was created
to counter
attack the Mondols. Finally in 1295 Mongol ruler Ghazan
Khan, converted to Islam, and declared it once again
religion of
the country. Ghazan also took steps to improve the economic
conditions. Cities such as Tabriz, Shiraz, and Esfahan,
which were ransacked during the Mongol invasion, were
once again
restored as cultural centers. From 1335 to 1380 unrest
in many areas led to a weakening of the rulers. In 1381
Tamerlane
the Turk attacked again and destroyed more of Iran's cities.
