Queen Elizabeth expressed her sadness over the loss of a "deeply valued" friend, who passed away on Tuesday, Sept. 29, at a hospital in the U.S. His Highness Sheikh Sabah Al Ahmad Al Sabah of the Kuwaiti royal family struggled with an undisclosed medical condition.

The Queen was one of the first heads of state to send her message of condolences to Kuwait's newest Emir, Crown Prince Sheikh Nawaf al-Ahmed, who took over the throne following Sheikh Sabah's death. The former ruler was Sheikh Nawaf's older brother. 

In her statement, Her Majesty said that she was saddened to hear about His Highness' passing and that she is offering her condolences to the new Emir and the people of Kuwait. The monarch said that the British royal family share "a long history of close companionship" with the Kuwaiti royals. Queen Elizabeth recalled that Sheikh Sabah devoted his life to service and forged to understand faiths and nations with his humanitarian causes. 

Queen Elizabeth also reflected on His Highness' last state visit to the U.K. in November 2012 and told the new Emir that the two families' alliance will continue. 

The government of Kuwait announced Sheikh Sabah's death Wednesday as his body was flown out of the U.S. for his burial in his native land. The monarch had been seeking treatment at the Mayo Clinic since July but the cause of his death was not disclosed to the public. He was 91 years old. 

Sheikh Sabah ascended as the ruler of Kuwait in 2006 after his cousin stepped down from the throne. But, boosted the country's foreign policy for the last 50 years as its former foreign minister. 

According to former Prime Minister Tony Blair, His Highness was deeply respected in the Middle East region and was the mediator of conflicts in the region. The King of Jordan, Abdulla II, referred to the ruler as their big brother and their leader. 

Meanwhile, Queen Elizabeth's first and only visit to Kuwait was more than 40 years ago. In February 2019, the Kuwait National Museum set up an exhibit to mark this historical trip that helped protect the country's "territorial integrity" in the Gulf region.  

But, while the Queen was not able to return to Kuwait, members of the royal family visited the country on her behalf, including Prince Charles, Princess Diana, Prince Andrew, Princess Anne and Camilla, the Duchess of Cornwall.