The Australian Supreme Court ordered to make public the correspondence written by the Queen Elizabeth II before the 1975 dismissal of then Australian Prime Minister Gough Whitlam.
The court ruled that the letters that the monarch had sent to Governor General John Kerr were in the public domain, according to the BBC.
Kerr fired Whitlam three years after he was elected prime minister, which led to a deep constitutional crisis. The reasons for his resignation are still being discussed; some experts believe that the UK and even the US tried to suppress the reformist ideas of the politician.
More than 200 letters have been kept sealed in the National Archives since 1978, but on Friday the High Court of Australia ruled that they could be accessed in the national interest.
The contents of the the letters between the Queen and Sir John are unknown.
In 2018, the historian Jenny Hocking demanded that the correspondence be published, but the Australian federal court refused the plaintiff to release the Queen's letters.