Prince Karim Al-Husseini, the Aga Khan - spiritual leader of the Ismaili Muslim community - passed away at the age of 88 on Tuesday in Lisbon, Portugal, surrounded by family.

His death has drawn widespread tributes, including from King Charles, who expressed deep sorrow over the loss of his longtime friend.

According to a royal source, the King, who had maintained a close personal friendship with the Aga Khan for many years, was "deeply saddened" by his passing.

The Aga Khan, who led millions of Ismaili Muslims worldwide, was a respected global figure known for his philanthropy and leadership.

His foundation, the Aga Khan Development Network (AKDN), is renowned for its work in improving healthcare, education, and economic development across several countries.

The Aga Khan’s passing has also prompted reflections on his long-standing connection with the British royal family. Notably, he shared a bond with Queen Elizabeth II, particularly over their shared love of horse racing.

The Aga Khan was often seen attending Royal Ascot with the Queen, and he was also the owner of Shergar, the legendary Derby-winning racehorse famously kidnapped in 1983.

In recognition of his contributions, Queen Elizabeth honored the Aga Khan with a dinner at Buckingham Palace in 2008. He had been granted the title of “His Highness” by the Queen in 1957, just weeks after being named the heir to the 1,300-year-old dynasty founded by his grandfather, Aga Khan III.

The Aga Khan’s influence extended to the younger generation of the British royals as well. In 2019, Prince William and Princess Kate visited the Aga Khan Centre in London, where they met with British-Pakistani business leaders, artists, and other prominent figures.