About seventy years ago this summer, German war chiefs were busy devising Unternehmen Grün or Operation Green: Nazi Germany’s planned invasion of Ireland. The plan has recently come to light. Dublin was earmarked by the Nazis as one of six regional administrative centres for Britain and Ireland right after Dunkirk when an allied collapse seemed imminent. The Germans thought it crucial that their advancing units reach Ireland as soon as possible after the initial invasion. The plan would have seen the fourth and seventh infantry divisions of the Germany Army being deployed to Ireland. The German 4th army corps in particular had a brutal reputation in battle and inflicted many civilian casualties as they secured the Polish corridor to Warsaw during the invasion of Poland in 1939. Their advance, had the fourth and seventh been deployed to Ireland, would have been rapid – up to 100km a day, and their brutality would have been beyond doubt.