Perennial champion Western Australian stallion Blackfriars has been euthanised at the age of 21 after breaking a leg.
The son of Danehill underwent surgery for colic and broke a leg when getting up.
"I'm absolutely shattered," Scenic Lodge general manager Jeremy Smith told the West Australian.
"It was a straightforward colic operation and he went to get up and broke his leg. We had no option but to put him down.
"He was a beautiful horse and was still at the top of his game.
"He had just covered 90 mares this spring."
The champion sire in the west for the past seven seasons, Blackfriars was bred by Swettenham Stud and carried the colours of the late Robert Sangster to victory over Shogun Lodge and Diatribe in the 1999 Victoria Derby before retiring to Scenic Lodge.
He covered his first book of 81 mares in 2001 at a fee of $7,700, which rose to as high as $22,000 in 2013.
His two best horses Black Heart Bart and Playing God were born four years apart.
Playing God won consecutive runnings of the Group 1 Kingston Town Stakes in 2010 and 2011. Playing God's first crop of 2yo's hit the track this season.
The gelded Black Heart Bart has five Group 1 wins to his credit to date while banking a tick under $4 million.
Blackfriars has sired 36 stakes winners to date and produced his 400th individual winner last week.