Herat dates back to the Avestan times and was traditionally known for its wine. The city has a number of historic sites. During the Middle Ages Herat became one of the important cities of Khorasan, as it was known as the Pearl of Khorasan.
The fall of the Sassanian dynasty by the invading Muslim Arabs led to the adaptation of Persian architectural forms for Islamic religious buildings in Iran. Arts such as calligraphy, stucco work, mirror work and mosaics became closely tied with the architecture of mosques in Persia (Iran). An example is the round-domed rooftops which originate in the Parthian (Ashkanid) dynasty of Iran.
Most mosques also feature one or more domes, called qubba in Arabic. While not a ritual requirement like the mihrab, a dome does possess significance within the mosque—as a symbolic representation of the vault of heaven.