Teddy Grimthorpe described Criquette Head-Maarek as "special for Juddmonte" after the Chantilly trainer announced her intention to retire following a long and highly-successful 40-year career.
Juddmonte Farms' Khalid Abdullah has been Head-Maarek's longest-serving owner, with an association going back to the early 1980s.
They have enjoyed many big-race triumphs, including with Special Duty, who completed the English and French 1000 Guineas double in 2010.
"Their association goes back well over 30 years," said Grimthorpe. "She's been a fantastic trainer for us. She trained the winners of 250 races, notably Special Duty, who was champion two-year-old and won the Guineas.
"American Post was a very vital Group One winner. When he won the French 2000 Guineas (in 2004) it completed a clean sweep of home-bred French and English Classic winners for Prince Khalid. That was a very big day.
"More recently we've had Epicuris, who won the Grand Criterium de Saint-Cloud (in 2014).
"Above all, her and her family have given tremendous service to Prince Khalid and she's been a special trainer for Juddmonte."
Head-Maarek believes being given a free-hand is important for a trainer.
She said: "Prince Khalid has been with me for so many years. He is the owner who has stayed with me longest.
"He had confidence in me and that is very important for a trainer. You are free to do what is good for the horses and that is the main thing."