Complex sentence: On the morning of November 10,1918, the office received a top-secret coded message from Europe stating that effective at 11 am on the next day (November 11,1918), all fighting would cease on land, sea and in the air.
Split into simpler sentences: On the morning of November 10,1918, the office received a top-secret coded message from Europe. It stated that effective at 11 am the next day (November 11,1918) all fighting would cease on land, sea and in the air.