"She made us and so many other people happy," the prince said during the memorial he and brother Prince William organized to remember the princess, who died in a car crash in Paris 10 years ago Friday with her companion, Dodi Fayed, and their driver, the BBC reported.
Former members of the princess's staff, the bridesmaids and page boys from her 1981 wedding, and representatives of charities and organizations she championed also were on the guest list.
Prince William read from St. Paul's letter to the Ephesians, which asked for inner strength.
The service included selections from the princess' favorite classical composers Rachmaninov and Mozart and four hymns, concluding with "I Vow To Thee, My Country," her favorite.
The service also included two prayers written by Archbishop of Canterbury Rowan Williams.