sentences:  It is considered to be one of the holiest Islamic sites in Egypt.Some Shia Muslims believe that Husayn's head ("ra's mubarak") is buried on the grounds of the mosque where a mausoleum is located today and considered to be what is left of the Fatimid architecture in the building.Following the beheading of Hussain ibn Ali in Iraq during the Battle of Karbala, in 1153 his head was sent to Cairo, Egypt to be protected by building a mausoleum for it completed in 1154.