As Queen Elizabeth II prepares to mark the 70th year of her reign, she was hit by a series of tragedies and scandals, but she has braved them all with a positive spirit.

The monarch lost Prince Philip, her husband of 73 years, in April this year. Two of her children were hit by serious scandals, as Prince Charles's closest aide was accused of promising a Saudi billionaire British titles in exchange for a donation to his charity, while a sex abuse lawsuit was filed against Prince Andrew. Meanwhile, the Queen had to also deal with the allegations levelled against Buckingham Palace by her grandson Prince Harry and his wife Meghan Markle.

According to a report in People magazine, the 95-year-old coped with all the heartbreak, scandal, and transition because she is "mentally disciplined." A source close to the British monarch said, "She keeps things a little separate between family and official issues because otherwise, it becomes overwhelming."

Ingrid Seward, longstanding biographer of the Queen, said that "her ability to compartmentalise has been extremely helpful in her life" as she juggles her family with her public role. Seward said, "Fundamentally she puts things in a box and says 'that can be dealt with on Thursday,' for example."

The biographer explained, "She won't let things crowd in on her. She is mentally disciplined and that has helped her through these 70 years. It has enabled her to deal with all the things and not allow things to overwhelm her."

Seward added that this compartmentalising also explains the Queen's ability "to be able to still be working at this age."

Meanwhile, the insider noted that the Queen might have been struggling with her physical health, but "her face is clear and cheerful and wide-eyed." The source explained, "this is not someone who life is getting down. Her phlegmatic nature and her shock absorbers are such that she can take the setbacks."

The insider added that the Queen also gets help from "her temperament and religious faith," and "can carry on for some time."

Another source who knows the monarch well said that she is ready to host a family Christmas celebration at Sandringham House in Norfolk, but she will struggle with not having her husband by her side for the first time in over seven decades. "She will be missing his companionship deeply. But she is a very stoic person," they said.

Sally Bedell Smith, author of "Elizabeth the Queen: The Life of a Modern Monarch, added, "I am sure she had plenty of time to prepare for it (Prince Philip's death. But I don't think anyone should underestimate that, however resilient, however faith-based and however strong she is, this is a confidant who is no longer there."

Queen Elizabeth II
Queen Elizabeth II attended last year's ceremony at the Cenotaph, which commemorates military veterans and the fallen in all conflicts since World War I the First World War and services across Commonwealth countries remember servicemen and women who have fallen in the line of duty since WWI. Photo: POOL via AFP / Aaron Chown