Lieutenant General Sir Iven Giffard Mackay, KBE, CMG, DSO & Bar, VD (7 April 1882 – 30 September 1966) was a senior Australian Army officer who served in both world wars.

Mackay graduated from the University of Sydney in 1904 and taught physics there from 1910 until 1914, when he joined the Australian Imperial Force shortly after the outbreak of the First World War.

The eldest of three children, he was the only son of the Reverend Isaac Mackay, a Presbyterian minister from Armadale, Sutherland, Scotland, and his Canadian wife Emily Frances, née King.

[3] Mackay had served in the Newington College cadet unit, reaching the rank of sergeant and winning a trophy in 1899 for being the school's best rifle shot.

[4] Mackay joined Sydney Church of England Grammar School in 1905, teaching various subjects and coaching the rowing and rugby teams.

[7] In October 1914, Mackay suffered a riding accident and was taken to Royal Prince Alfred Hospital with a punctured lung and broken ribs.

He sailed for Egypt with the 1st Reinforcements of the 13th Infantry Battalion, departing Sydney on the transport Berrima on 19 December 1914, arriving at Alexandria on 31 January 1915.

He observed the landing at Gallipoli from the transport SS Lake Michigan, but did not go ashore with the battalion, as his job was to take care of the horses.

[2] Heavy casualties in the early fighting had depleted the officer ranks and Mackay was promoted to major on 14 July 1915, and given command of a company in August.

As they stood at this desolate corner (the most actively shelled in Pozières), surrounded by shredded tree-trunks and the dead, a panting messenger stumbled up to them with an envelope marked "Urgent and Secret".

[24] Acting brigade commander again during the Second Battle of Bullecourt in May, Mackay was mentioned in despatches for the third time,[25] and awarded a bar to his Distinguished Service Order.

[26] Along with Brigadier General H. Gordon Bennett and others, Mackay received personal congratulations from Field Marshal Sir Douglas Haig.

[4] On 6 June 1918, Mackay was heading on leave to London to visit his wife, who had managed to reach England after a long battle with wartime travel restrictions, when he was stopped and turned back at Boulogne by British military police.

[34] After the end of the war Mackay took advantage of Brigadier General George Long's education scheme to study physics at Emmanuel College at the University of Cambridge under Ernest Rutherford.

When, in December 1939, Mackay's daughter Jean married Lieutenant W. H. Travers,[41] the grandson of Major General William Holmes;[42] the reception was held at Cranbrook.

[43] Following formation of a second infantry division for the Second Australian Imperial Force in 1940, Lieutenant General Sir Thomas Blamey was elevated to command of the newly created I Corps.

Colonel Alan Vasey, his assistant adjutant and quartermaster general, asserted that Mackay lacked the ruthlessness to remove Militia officers who were not performing well.

In action he never knew the meaning of fear ..."[46] His appointment to command the 6th Division meant that Mackay led its—and the Australian Army's—first battles of the war.

They watched him sit in the open during attacks; on one such occasion on 19 April 1941, Mackay waited out a two-and-a-half-hour raid when his car was hit and his driver wounded.

[58] Mackay resolved to reform the battalions that had been destroyed in Greece, and to rebuild his shattered division from the remnants that had been evacuated to Alexandria.

In July 1941, Ernest Turnbull, representing the motion picture industry, approached Menzies and several members of his Cabinet about the possibility of Mackay becoming Chief Commonwealth Film Censor.

Official historian Dudley McCarthy noted that: If Mackay had been in any way deceived by the grandiloquence of his new title his illusions were soon dissipated when he assumed command on 1 September.

In short his command was far more circumscribed than he might have expected, with the added disadvantage of calling for a political finesse to the possession of which he laid few claims.

The period was a quiet one, with no major operations being carried out, and Mackay handed back to Herring and returned to command of the Second Army at Parramatta, New South Wales, in May 1943.

[4] In November 1943, it was announced that Prime Minister John Curtin, with Blamey's approval, had appointed Mackay as High Commissioner to India.

[2] India was not yet independent, but was about to become so, and Mackay met with future leaders Jawaharlal Nehru, Indira Gandhi and Muhammad Ali Jinnah.

[75] Mackay and the Minister for External Affairs, Dr H. V. Evatt, supported Indian independence, while expressing the hope that India would remain in the British Commonwealth.

This time he also revisited the Gallipoli battlefields, sailing to the Dardanelles on HMY Britannia as a guest of Field Marshal Prince Henry, Duke of Gloucester.

[78] Mackay died at his home in East Lindfield, New South Wales, on 30 September 1966 and was cremated after a service at St Stephen's, Sydney.

[2] Veterans lined the streets and he had ten generals for his pallbearers: Herring, Woodward, Stevens, Pulver, Stevenson, Macarthur-Onslow, Dougherty, Harrison, Cullen and Galleghan.