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
Easter Rising suppressed the Rising. Pearse agreed to an unconditional surrender on Saturday 29 April, although sporadic fighting continued until Sunday, when word reached the other rebel positions. After the surrender the country remained under martial law. About 3,500 people were taken prisoner by the British, many of whom had played no part in the Rising, and 1,800 of them were sent to internment camps or prisons in Britain. Most of the leaders of the Rising were executed following courts-martial. The Rising brought physical force republicanism back to the forefront of Irish politics, which for nearly 50 years had been dominated by