Al Qaeda supposedly attacks on anniversaries of important dates, or so it has been speculated by some. October 7 would be a good date, if you believed that, considering that the war in Afghanistan started on October 7, 2001.
October 7, 1571, was the date of the battle of Lepanto—a major Christian naval victory over the Ottoman Turks.
also, Yom Kippur starts at sundown.
Also, carbon paper was invented on October 7, 1806. Could be a copycat terrorist plot...