On 4 May 1940, the Vatican advised the Netherlands envoy to the Vatican that the Germans planned to invade France through the low countries. With the blessing of the Pope, the Vatican sent a coded radio message to its nuncios in Brussels and The Hague. The messages were intercepted by the Nazis
On May 5 1940,Pope Pius XII shared the intelligence gathered by Vatican agents that Germany was planning on invading the Low Countries with the Princess of Piedmont Marie José, who was the sister of King Leopold III of Belgium and wife of Italian Crown Prince Umberto.
On the same day, a massive German armoured motorised column many miles long was spotted driving west through the Ardennes forest but the Belgian Army did not respond.
History of Sorts 