Some dates specialize. May 7 has, across three separate centuries and two world wars, developed a recurring relationship with the moment empires and armies admit they cannot continue. The pattern is not coincidence. It is the calendar doing what it does — accumulating weight until a date no longer belongs only to the year it inhabits. On May 7, 1915, the RMS Lusitania was struck by a German torpedo fourteen miles off the southern coast of Ireland.