Senior members of the Royal Family were among about 2,000 guests who gathered in Chester to celebrate the life of the sixth Duke of Westminster.
The Duke and Duchess of Cornwall and the Duke and Duchess of Cambridge attended the memorial service at Chester Cathedral.
Major General Gerald Cavendish Grosvenor, a close friend of the Royals, died of a heart attack aged 64 on August 9.
He was taken ill during a visit to his Abbeystead Estate in Lancashire before he was transferred to Royal Preston Hospital.
Members of the Grosvenor family attended a "quiet" private funeral service in the days after the Duke's death, but yesterday's invitation-only ceremony was a more public occasion.
The Duke married Natalia Phillips - a godmother to Prince William - in 1978. They had one son, Hugh, and three daughters, Lady Tamara, Lady Edwina and Lady Viola.
The dukedom passes to Hugh (25), who is Prince George's youngest godfather.
Also attending the service were the Duke of Kent and Prince and Princess Michael of Kent, along with employees of the Grosvenor estate and representatives of the numerous charities with connections to the sixth Duke.
Several roads in the city centre were closed to traffic as people gathered behind barriers outside the cathedral to pay their respects.
The Grosvenor family's ancestral home is Eaton Hall in Eccleston, near Chester. The Duke was buried in the village.
At the time of his death, the landowner was worth about £8.65bn, according to Forbes, making him the 68th richest person in the world, and third in the UK.
He owned 190 acres in Belgravia, adjacent to Buckingham Palace and one of London's most expensive areas, as well as thousands of acres in Scotland and Spain.
Lady Edwina Snow, the late Duke's second daughter, wife of TV historian Dan Snow and goddaughter of Diana, Princess of Wales, read her own "A letter to my father", an excerpt from which read: "You taught me so much. Fight for what you believe in. Don't ever give up. If you are knocked down, dust yourself off... and get back on your feet".