SilenceThe central element of the ANZAC Day ceremony is the one minute period of silence.  The history of this period of silence is as follows:

On the occasion of the Armistice on the 11th November 1918, the boisterous behaviour of the public and the noise of tin trumpets, crackers etc., appalled Edward George Honey, a journalist from Melbourne working in London, because those who had made the supreme sacrifice seemed to have been forgotten.  On the 8th May 1919, a letter in the “London Evening News“, under the pen-name “Warren Foster” proposed a period of silence for national remembrance and appealed for a five-minute silence amid the celebrations planned for the first anniversary of the of the Armistice to honour the sacrifice of those who had died.  The letter was actually written by Edward George Honey.
In October 1919, Lord Milner put to the King a suggestion made by Sir Percy Fitzpatrick, a South African, for a period of silence on Armistice Day in all the countries of the empire. Fitzpatrick’s idea had its origins in a period of silence that was observed at noon in Cape Town following heavy losses among the South African Brigade on the Western Front; this observance had continued until the end of the war.
The King readily agreed to the proposal, but after a trial of a five minute silence with the Grenadier guards at Buckingham Palace, at which both Honey and Fitzpatrick were present, the period of silence was shortened to two minutes.  The connection between Honey and Fitzpatrick, and their ideas, if any existed at all, is unclear.  On the 6th November 1919, George V sent a special message to the people of the Commonwealth:  I believe that my people in every part of the Empire fervently wish to perpetuate the memory of that Great Deliverance, and of those who laid down their lives to achieve it. The King continued to ask that “a complete suspension of all our normal activities” be observed for two minutes at “the eleventh hour of the eleventh day of the eleventh month” so that “in perfect stillness the thoughts of everyone may be concentrated on reverent remembrance of the glorious dead”.
Two minutes of silence was first observed in Australia on that first anniversary of the armistice, at 11-00am on the 11th November 1919, when they paused and stood in silent tribute to the men and women of the Australian Imperial Force who died on battlefields in the Middle East, Gallipoli and Europe.
After the end of World War II, the Australian and British governments changed the name to Remembrance Day.  Armistice Day was no longer an appropriate title for a day which would commemorate all war dead.
In November 1997, the Governor-General, Sir William Deane, issued a proclamation formally declaring the 11th November as Remembrance Day and urging all Australians to observe one minute’s silence at 11-00am on the 11th November each year to remember those who died or suffered for Australia’s cause in all wars and armed conflicts.  It is also still appropriate for two minutes silence to be observed.
The period of silence has over the years been incorporated into ANZAC Day, Remembrance Day and other commemorative ceremonies.