Queen Elizabeth II sure did experience a lot of challenges in her nearly seven decades of reign. Just recently, she, along with the rest of the British Royal Family faced a huge hurdle as the Duke and Duchess of Sussex announced that they are already stepping down as senior royals.

While the couple's royal exit was already concluded, which will take in effect come the spring of this year, the controversies surrounding the monarchy continue to develop today. Even so, these things were deemed to be not in par with what she experienced in 2017.

According to Daily Express, Queen Elizabeth II committed her "biggest mistake" in the last decade during 2017 when she reportedly allowed Prince Charles and Prince Andrew to oust her Private Secretary, Sir Christopher Geidt after serving her for ten years. The Lord's exit then was said to be a product of "power struggle" involving the primarily the Wales household, especially the Heir Apparent.

As revealed, this came after when the Prince of Wales had indifferences with the Queen's "most trusted aide" over the "handling of the transition of power" to Prince Charles to the throne. It was claimed that Lord Geidt "upset" the next person in line to the throne.

The Royal Household, however, issued a formal statement about the matter as per Royal Central. It was said that Sir Christopher Geidt is "stepping down" after ten years of being Queen Elizabeth II's Private Secretary.

While the official statement revealed that this was seemingly a choice made by Lord Geidt, several sources from various publications attested that he was "forced out" after the alleged "power struggle" between the Buckingham Palace and the Prince of Wales. In addition, sources further revealed that Prince Andrew "backed" his brother to oust the Queen's aide.

In the same publication, other sources insisted that the two princes "shared a great dislike" toward Sir Christopher Geidt. As suggested, the Duke of York's aversion was largely fueled due to Lord Geidt's reported "heavy" control of his expenditures. Others, however, contended that it was about Prince Andrew's fury given that the royal aide allegedly played a significant role in "removing" the Duke as the UK's trade envoy.

Whatever the case, though, the Private Secretary's exit remains to be seen as Queen Elizabeth II's "biggest mistake" in the past decade. In the same year, she also lost Prince Philip's assistance as the Duke announced his retirement.

Upon losing her two best advisors within the monarchy, it was said that the "Queen has appeared weak" as if she can no longer control the Royal Family.