Jameh Mosque of Kashan, built during Seljuq dynasty in 1779 AD, is the oldest historical structure in Kashan. The plan of the mosque is simple. There is a Howz in the courtyard in front of the Ivan, which leads to the inner space of the dome and also two Shabestans at grade of the courtyard and a winter Shabestan below the surface of the courtyard.
Its only brick minaret is located in its southeastern corner. On the bottom part of the minaret, there is a Kufic inscription made by embossed brick. On the inscription the construction date of the minaret is mentioned, which is 1074 AD. The minaret is the third oldest minaret in Iran, which has an inscription. It is said that there had been a fire temple from the pre-Islamic period in this place and after the islamization of Persia the fire temple has been converted to the mosque.
Large old mihrab of the mosque, like minaret, seems to belong to the Seljuk era. It has an exquisite stucco, on which there are verses from Quran about the virtue of Friday prayer. It seems that this large mihrab has been destroyed intentionally because of its false direction of Qibla. Instead of this mihrab a smaller one has been built in the true direction of Qibla during the reign of Tahmasp I.