After the martyrdom of Imam al-Husayn (a) and his companions, a clan of Banu Asad buried their corpses where they were martyred. The only sign on Imam al-Husayn's (a) grave at the time was a lump of soil. When al-Mukhtar al-Thaqafi triumphed in his uprising for the vengeance of Imam al-Husayn (a) in Sha'ban, 65/March 685, he built the first mausoleum for Imam al-Husayn's (a) grave with a dome made of bricks and plasters.
Visiting Imam al-Husayn's (a) shrine is a Shiite practice recommended in Shiite hadiths. Most visitors or pilgrims congregate in Imam al-Husayn's (a) shrine on Ashura, Arba'in, and mid-Sha'ban. In Shiite fiqh, there are rulings specific to Imam al-Husayn's (a) shrine and his soil. Since many Shiites visited Imam al-Husayn's (a) mausoleum, Harun al-Rashid ordered some of his soldiers to destroy the mosque built on Imam al-Husayn's (a) grave as well as the one built on Abu l-Fadl al-'Abbas's (a). Harun had also asked them to cut the cedar tree that had grown near Imam al-Husayn's (a) grave (and was used as a sign for the grave) and to raze the grave.
Through out time the holy shrine reconstructed and destroyed many times. Read more...