Kate Middleton is learning more about her family’s connection to World War I ahead of the 100th anniversary of Armistice Day on Nov. 11.

The royal paid a visit to the Imperial War Museum London, where she viewed letters relating to the three brothers of her great-grandmother, all of whom fought and died in World War I. She was shown several documents, including a letter of condolence from the Keeper of the Privy Purse at Buckingham Palace.

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Ahead of viewing the letters, which are part of the IWM’s Documents Archive, Kate took a brief tour of the First World War Galleries, where she will be shown elements of the galleries that relate to the experience of her relatives. She met historians, curators and the fellow descendant of a First World War soldier.

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Princess Kate wore a structured blue dress with three-quarter length sleeves for the occasion, paired with beige heels and her hair styled in her signature bouncy blowout.

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Kate’s great-great-grandfather, Francis Martineau Lupton, had five children. His three sons — Francis, Maurice and Lionel — were all killed in action while serving during the First World War. During their time in the trenches, the brothers corresponded with their sister Olive, Kate’s great-grandmother who worked as a nurse, and her husband Lieutenant Richard Noel Middleton, Kate’s great-grandfather.

Two younger brothers, Lieutenant Lionel Lupton and Captain Maurice Lupton, died within three days of each other in 1915 when they were just 24 and 28, respectively.

The eldest brother, Major Francis Lupton, served with the 8th Battalion West Yorkshire Regiment and was killed by a bomb in February 1917, when he was 31.

The mother of three, 36, spoke about her great-grandmother’s experience working as a nurse during WWI, caring for wounded servicemen in a field hospital, during a February visit to St. Thomas’ Hospital in London.

“This campaign means a lot to me personally. My great-grandmother and grandmother were both volunteer nurses,” she said in a speech. “They would have learned first-hand from working with the Voluntary Aid Detachment and the Red Cross about the care and compassion that sometimes only nurses can provide.”

This article originally appeared on People. For more stories like this, visit people.com.