"Today we remember and honour all those who sacrificed so much for us. We shall never forget!" tweeted Beatrice, while her husband Edo Mapelli Mozzi added: "You will never be forgotten. #RemembranceSunday."
Eugenie, 30, shared an image of her royal wedding flowers from 2018, and said: "Today on Remembrance Day we remember all those who have given their lives in wars so bravely. The Unknown Warrior in Westminster Abbey honours all those. As with tradition, my bouquet was laid on there."
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The two sisters followed in the footsteps of the Queen, the Duchess of Cambridge and the Duchess of Sussex by laying their wedding bouquets on the Grave of the Unknown Warrior to honour Britain's fallen soldiers.
The Queen Mother was the first royal to start this thoughtful tradition in 1923, when she placed her own bouquet at the grave of her brother Fergus - who was killed in 1915 at the Battle of Loos during the First World War - after marrying George VI. This touching move inspired generations of royal brides to leave their own bouquets placed on the tomb – usually a day after the wedding.
The flowers Princess Beatrice laid on the Grave of the Unknown Warrior
The grave, which lies in the nave of the Westminster Abbey, is the final resting place of an unidentified World War One soldier who was buried on Remembrance Day in 1920. The monument stands as a tribute to those who lost their lives in the First World War and to all those who have died since in international military conflict.
On Saturday, the Queen paid her respects as she left a replica of her wedding bouquet on the grave. The bouquet of white and lilac orchids, myrtle and greens was created by a palace florist to reflect the one she carried on her wedding day.
Princess Eugenie laid her flowers following her 2018 wedding
A royal source said: "The grave of the unknown warrior is as relevant and poignant today as it was when Her Majesty's grandfather and father stood in the abbey at its side 100 years ago. It holds enormous significance for the country and the royal family.
"The Queen was keen that the centenary was marked appropriately. A simple but deeply personal act reflecting a tradition started by her mother 97 years ago felt the right thing to do."
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