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Camilla Duchess of Cornwall, Queen Elizabeth II and Monty Roberts

Queen Elizabeth’s horse trainer Monty Roberts found he had tears rolling down his cheeks during the late monarch’s moving committal service.

The equestrian expert from California who worked with the Queen was in attendance at the service at St. George’s Chapel in Windsor Castle on Monday afternoon.

“I’ve spent a lot of time at Windsor Castle. But I’ve never seen it like that. It was just a different world,” he tells PEOPLE.

Roberts joined more than 800 people at the Queen’s committal service, an event with a more intimate feel than the state funeral earlier in the day. The chapel’s pews were filled with some of the people who knew the Queen best — in addition to members of the royal family, the congregation was made up of past and present members of the Queen’s Household, including from the private estates.

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The Duchess of Sussex, the Duke of Sussex, Princess Charlotte, the Princess of Wales, Prince George, and the Prince of Wales during the Committal Service for Queen Elizabeth, at St George’s Chapel in Windsor Castle on September 19, 2022 in Windsor, England. The committal service at St George’s Chapel, Windsor Castle, took place following the state funeral at Westminster Abbey. A private burial in The King George VI Memorial Chapel followed. Queen Elizabeth II died at Balmoral Castle in Scotland on September 8, 2022, and is succeeded by her eldest son, King Charles III.

“Queen Elizabethhas been more than just a friend for 35 years. I was worried about being emotionally disturbed at the funeral — a lot of people do. I was worried about crying,” Roberts, 87, who sometimes has difficulty standing for long periods due to an auto-immune condition, says.

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He adds, “I was doing fine and my wife Pat said, ‘Go ahead and sit down,’ as she thought I was going to fall.”

Roberts shares that seeing one moment in the service made him emotional.

“When they brought in the coffin, I stood up and told myself, ‘You’re not going to cry,’ " he shares. “Then it hit me, and the water just started running out of my eyes. I thought, ‘What is this?’ It was really tough on me.”

Queen Elizabeth at the WIndsor Horse Show on May 13, 2022.Chris Jackson/Getty Images

Queen Elizabeth II watches the horses from her Range Rover at The Royal Windsor Horse Show

After the service, Roberts asked a surgeon friend who was in the congregation about his reaction, and he was told: “We’ve learned about that. It’s inner sadness or anxiety that you couldn’t hide — and the water just runs straight out without you gasping or crying in the usual way.”

“He made me feel a lot better because I do have inner sadness,” Roberts adds.

“He has been such an incredible asset to her life and stable,” says Roberts. “I don’t know how Terry did it today. He was as good as gold. He hosted us afterward, and he was okay. He was smiling and laughing — he’s handled it very well.”

Roberts also reconnected withQueen Camilla, who he also worked with in the past.

“She’s pretty good around horses, and I think we’ll be together in the same goal the Queen had to reduce violence with horses,” he says.

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“For 6,000 years, horses had been broken with a lot of violence, taking four to six weeks before they could be ridden,” Roberts said. “I could train horses to take their first saddle and rider in less than 30 minutes without any violence.”

While some of the Queen’s courtiers were suspicious of his methodology in those early days,Queen Elizabethsupported him as he took his message of compassionate horse training to the world. And she urged him to write a book — hisThe Man Who Listens to Horseshas since sold more than 6 million copies since 1997.

“I have been to 41 countries in her name,” said Roberts.

source: people.com