Teddy Grimthorpe is stepping down from his long-standing role as racing manager to Juddmonte Farms after 22 years.
In a position he took over in 1999, Grimthorpe managed all of the late Khalid Abdullah's horses in Europe, overseeing such greats of the Turf as Frankel and Enable.
He said in a statement: "I have always felt that the time for me to stand down from Juddmonte would be when Prince Khalid was no longer involved. It has been a huge privilege to work for the Prince and his family, and with the outstanding Juddmonte team, which has been so successful for so long.
"Of course I am sad to leave. But, with the Prince's death two months ago and over 20 years as his Racing Manager, now is the right time. I leave an organisation in great shape, which is supreme at what it does, and I have no doubt Juddmonte will continue to thrive and produce top-class homebred thoroughbred horses competing at the highest level on racecourses across the world."
Douglas Erskine Crum, chief executive of Juddmonte, said: "On behalf of Prince Khalid's family and all of us past and present at Juddmonte, I thank Teddy for all he has done to help the organisation be at the very top of its game year after year.
"He will be sorely missed, and we wish him the very best of good fortune for the future."
Grimthorpe - who was chairman of York Racecourse for nine years and remains on the board there - envisages spending more time in Yorkshire in the future, but intends to stay involved in the racing industry in some capacity.
He said: "I've just had the most tremendous time. It's been an absolute honour and privilege to have worked for Prince Khalid and his family.
"This just seemed right (time to leave). I still want to remain active in the industry, and there are some things I want to pursue back in Yorkshire. Life will go on.
"Obviously I've given it a great deal of thought and I haven't taken the decision lightly. I've been unbelievably lucky, I really have."
A host of brilliant horses have worn the Juddmonte silks throughout Grimthorpe's tenure, with sprinters such as Oasis Dream, milers like Kingman and Derby and Prix de l'Arc de Triomphe winner Workforce all sporting the colours with distinction.
Two horses stand out for him, though.
"When Prince Khalid died and we looked back at the big moments, there were so many extraordinary horses who had won serious Group One races who hardly got a mention," he said.
"I think in terms of special moments, though, Frankel looms over everything. Seeing him develop, Sir Henry (Cecil) became a very close friend, as did all the Juddmonte trainers, but it was just the story around Frankel with how ill Henry was.
"Obviously I'm biased, but the day at York with him was very special - it was a day lot of people remember. Prince Khalid was there, Henry was very ill - and the crowd were beyond belief.
"I was waiting for Prince Khalid to arrive - and normally at York when there is a big crowd a lot of it is coaches - but this wasn't, this was a case of people getting in their car to go and see the horse.
"I've never seen the paddock as crowded - it was like Cheltenham - and of course his his performance was outstanding. People still come up to me to talk about that day.
"Then of course, we've had Enable the last few years. She had the most remarkable personality, and her relationship with Frankie (Dettori) was something special too, which all added to the story."