The Imamzadeh Hossein is the grave mosque of a son of the 8th Imam Ali al-Ridha ("Hazrat-e Reza") in Qazvin , Iran that the Safavids - Shah Tahmasp I built in the mid-16th century as a pilgrimage center .
The namesake of the tomb is the biennial deceased son of Imam Hossein . This passed in transit with his father to Khorasan in Qazvin in 821 and was buried at the site . Later more people were buried from the Safavid dynasty bib . Tahmasp I , who had his seat of government in Qazvin , built the tomb . His daughter "Zainab Beygum" expanded it in 1630 , as is testified by a tile inscription .