Easter Rising in putting the rising off for only a day, although it greatly reduced the number of Volunteers who turned out. British Naval Intelligence had been aware of the arms shipment, Casement's return, and the Easter date for the rising through radio messages between Germany and its embassy in the United States that were intercepted by the Royal Navy and deciphered in Room 40 of the Admiralty. The information was passed to the Under-Secretary for Ireland, Sir Matthew Nathan, on 17 April, but without revealing its source, and Nathan was doubtful about its accuracy. When news reached Dublin of the capture
First Day of the Easter Rising Markievicz (Countess Markievicz), occupied St. Stephen's Green, digging trenches and commandeering vehicles to build barricades. They took several buildings, including the Royal College of Surgeons, but did not make an attempt on the Shelbourne Hotel, a tall building overlooking the park. Daly's men, erecting barricades at the Four Courts, were the first to see action. A troop of the 5th and 12th Lancers, part of the 6th Cavalry Reserve Regiment, was escorting an ammunition convoy along the north Quays when it came under fire from the rebels. Unable to break through, they took refuge in nearby buildings. The headquarters battalion,