The father of Danish Queen Mary, Professor John Dalgleish Donaldson, has died at 84 years old.
The Danish royal house announced the passing of Prof Donaldson on Sunday, just weeks after King Frederik X and Queen Mary visited Australia.
‘My heart is heavy, and my thoughts are grey. My beloved father has passed away,’ Mary said in a statement.
‘But I know that when the grief settles, the memories will brighten my day, and what will remain strongest is love and gratitude for everything he gave me and taught me.’
Denmark’s royal house said Prof Donaldson’s ‘health has been declining over the past few years’ and Mary visited him in late March.
The family will hold a private memorial service at a later date.
Prof Donaldson was a Professor of Applied Mathematics, born in Scotland on September 5, 1941.
He moved to Tasmania with his first wife, Henrietta Clark Horne, in November 1963.
Professor John Dalgleish Donaldson (pictured on March 23, 2026), father of Queen Mary, died in Hobart at age 84
King Frederik X and Queen Mary (above) visited her father in late March
Prof Donaldson (pictured with Queen Mary) had been suffering a decline in health ‘over the past few years’
The couple welcomed their daughter, Mary Elizabeth Donaldson, on February 5, 1972, in Hobart.
The now-Queen of Denmark arrived in Australia alongside King Frederik X for a six-day state visit running from March 14 to March 19 – the couple’s first official trip to the country since ascending the throne in January 2024.
At the end of that trip, Mary set aside time to visit her father.
The retired mathematics professor had previously missed several significant family milestones due to his frailty – including Princess Isabella’s confirmation and Mary’s own coronation in Denmark.
Royal officials previously confirmed Mr Donaldson was unable to travel long distances because of his health.
Mary herself acknowledged the emotional reality at the time, saying: ‘He is getting to be an elderly gentleman and he is not well enough to take the long trip back to Denmark for a confirmation, but he is with us in our hearts.’
Queen Mary announces death of father at 84 after declining health: ‘My thoughts are grey’
King Frederik’s wife, Queen Mary of Denmark shared the death of her father, Professor John Donaldson, with a statement on Instagram
Queen Mary of Denmark shared some sad news on 12 April, taking to social media to announce the death of her father. Translated to English, a message shared on King Frederik and Queen Mary’s Instagram account read: “It is with great sorrow that Her Majesty, The Queen, announces that her father, Professor John Dalgleish Donaldson, has died in Hobart, Tasmania. He was 84 years.”
Captioning a black and white photo of Professor Donaldson, which was captured by King Frederik’s wife on 23 March 2026, was a statement from Mary: “My heart is heavy, and my thoughts are grey. My beloved father has passed away. But I know that when the grief settles, the memories will brighten my day, and what will remain strongest is love and gratitude for everything he gave me and taught me.”
The post also revealed that Professor John Donaldson’s health has been declining over the past few years and that the Queen last visited her father at the end of March, where they shared precious time together.
John Donaldson was a Professor of Applied Mathematics, born in Scotland on September 5, 1941. The family will hold a private memorial service at a later date.