Queen Elizabeth's representative in Australia fired a prime minister without warning the palace - or the prime minister - because "under the constitution the responsibility is mine", according to archived letters released on Tuesday.
In a November 11, 1975 dispatch, Governor-General John Kerr told the Queen's private secretary he took the unprecedented step to sack Prime Minister Gough Whitlam as Whitlam prepared to end a months-long budget standoff by calling a partial Senate election.
"I decided to take this step ... without informing the Palace in advance," Kerr wrote to former private secretary Martin Charteris on the day of Whitlam's dismissal.
"It was better for Her Majesty not to know in advance, though it is ... my duty to tell her immediately," Kerr added, according to the documents.
The release of 211 so-called "palace letters" pulls the veil from one of the great mysteries of Australian politics, and may reignite a conversation about whether the country should cut ties with Britain and become a republic.
Whitlam's firing remains one of the country's most polarising political events because it represented an unprecedented level of intervention by the Commonwealth.
Historians say the country was never told the full story, and in 2016 a historian sued the National Archives of Australia for access to letters between Kerr and the queen. The lawsuit failed on grounds that the letters were private, but the High Court overturned the ruling in May.
The letters show Kerr and Buckingham Palace discussed the political crisis gripping the country, and Kerr's role in it, for two months before Whitlam's sacking as the prime minister tried to get parliament to approve his Budget.
His efforts were rewarded, by the palace at least. The day after he sacked Whitlam, Charteris congratulated Kerr on his judgment.
"In not informing The Queen what you intended to do before doing it, you acted not only with perfect constitutional propriety but also with consideration for Her Majesty's position," he wrote.