Updated: March 18, 2019 at 4:39 pm

Multiple Grade I winner and star stallion Pioneerof the Nile (Empire Maker–Star of Goshen, by Lord At War {Arg}), perhaps best known for siring 2015 Triple Crown winner American Pharoah, has died suddenly at the age of 13, WinStar Farm announced. According to the farm, Pioneerof the Nile bred a mare Monday morning and started acting uncomfortable once he was back in his stall. He was en route to the clinic when he died.

“We are all extremely saddened by the loss of Pioneerof the Nile,” said WinStar Farm’s Elliott Walden. “He was a superior physical specimen, a Triple Crown sire, and a unique personality. All of us at WinStar are heartbroken.”

Bred and owned by Zayat Stables during his racing career, Pioneerof the Nile won both the 2008 GI CashCall Futurity and GI Santa Anita Derby and was runner-up in the 2009 GI Kentucky Derby. He entered stud at Vinery in 2010 and spent three years there before transferring to WinStar in 2013. He was a perennially among the leading sires and was represented by Eclipse 2-Year-Old champion Classic Empire in 2016.

Ahmed Zayat made his first foray into horse racing in 2005 and Pioneerof the Nile was at the forefront of his family’s breeding operation. It was that year that Zayat purchased his first broodmare, Star of Goshen, carrying the future Grade I winner.

Zayat took to twitter Monday to express his grief at the passing of his first homebred.

“I’m incredibly shocked and saddened by the sudden loss of my Pioneer of the Nile,” Zayat tweeted. “He was not only my first homebred he was one of my GREATEST. He was the proud father of American Pharoah and a true sire of sires. Pioneerof the Nile will be greatly missed by all of us here at Zayat Stables and by all of the racing and breeding world. Thank you to Bob Baffert for training him, thank you to WinStar Farm for standing him and caring for him these last years. He is gone way too soon, but never to be forgotten. It truly does take a Pioneer.”

Zayat’s son Justin echoed his father’s sentiments.

“I’m stunned and hurting from this news,” Justin Zayat tweeted. “It’s hard to even put into words what Pioneerof the Nile meant to me and to my family. He was the first horse we ever bred, who then became a stallion himself siring our Triple Crown champ American Pharoah. Pioneerof the Nile had true world-class intelligence, athleticism and personality. Thank you for all the victories, memories, and game-changing success you created for me, my family, and for the lives of everyone you touched.”

Pioneerof the Nile gave his first hint of talent on the racetrack with a third-place finish in the 2008 Lane’s End Breeders’ Futurity at Keeneland. Fifth behind Midshipman in the GI Breeders’ Cup Juvenile, he concluded his juvenile campaign with a win in the GI CashCall Futurity. He proved he was Triple Crown material when opening 2009 with three straight wins on the West Coast, taking the GII Robert B. Lewis S. and GII San Felipe S. before heading to Louisville with a one-length victory in the GI Santa Anita Derby. The dark bay looked like a likely winner at the head of the Churchill stretch on the first Saturday in May, but passed late by longshot Mine that Bird. Pioneerof the Nile was eased in the GI Preakness S. and was retired that July with soft tissue injury to his left front leg.

Pioneerof the Nile began his stud career at Vinery in 2010 before moving to WinStar in 2013. His initial stud fee at WinStar was $15,000. By 2019, with the stallion already represented by four champions and 11 graded stakes winners, it had soared to $110,000.

In addition to American Pharoah and Classic Empire, Pioneerof the Nile was also represented on the track by 2016 GI Shoemaker Mile S. winner Midnight Storm and 2014 GII Holy Bull S. winner Cairo Prince. His progeny have grossed over $35 million to date.

“He was nothing short of perfect,” said Tom Ryan of S.F. Bloodstock, a committed shareholder in the stallion. “A brilliant racehorse, a generational influence, and a cool customer. He started at the bottom and leaves an indelible mark on our industry. My heart goes out to [WinStar stallion manager] Larry [McGinnis] and his team who cared for Pioneerof the Nile every day at WinStar Farm.”

In the sales ring, Pioneerof the Nile was represented by three million-dollar sales in 2018. His weanling daughter out of Stopchargingmaria (Tale of the Cat) sold for $1.9 million to Mandy Pope’s Whisper Hill Farm at last year’s Fasig-Tipton November sale. A colt out of Pomeroy’s Pistol (Pomeroy) brought $1 million from Albaugh Family and Spendthrift at the Keeneland September Yearling Sale and a filly out of Graeme Six (Graeme Hall) sold for $1.05 million to bloodstock agent Shawn Dugan at the same auction.

During last week’s OBS March sale, Larry Best’s OXO Equine purchased colt by the sire out of Golden Artemis (Malibu Moon) for $1.2 million. Pioneerof the Nile also was represented by seven-figure juveniles at the 2016 Fasig-Tipton Florida sale and at the 2017 OBS March sale.

Pioneerof the Nile’s young graded-stakes winning sons have already made an impact in the sales ring. Triple Crown winner American Pharoah was represented by five seven-figure sales from his first crop at the yearling auctions last fall and he also had a weanling filly and a short yearling colt bring $1 million last winter. He towered over his fellow first-crop sires, with 67 yearlings selling for an average of $467,307 and he was the third overall leading sire at the Keeneland September sale.

The first crop of multiple graded stakes winner Cairo Prince was also popular in the sales ring. Led by a colt selling for $900,000 at the 2017 Keeneland September sale, Cairo Prince was the year’s second-leading first crop sire of yearlings. From his first 2-year-olds to hit the track, Cairo Prince was represented by graded stakes winner Cairo Cat, stakes winners Mihos, Giza Goddess, and Marquee Prince, as well as graded placed Pakhet.