The Destructiion of the Church of the Holy Sepulchre
"In the year 1009, al-Hakim, the Caliph of Egypt, ordered the Church of the Holy Sepulcher in Jerusalem destroyed. Workmen obeyed; and Yahia ibn Sa`id, an Islamic historian, wrote: "...the holy deed commenced on Tuesday, the fifth day before the end of the month of Safar of the year 400 of the Egira." Converting from the Muslim calendar would place the destruction on or about this day, October 17, 1009." Read the rest here.