https://www.si.com/longform/belmont/index.html

One of the trainers who worked at his farm, The Meadow, described Secretariat - whose name was really Big Red, Secretariat was just his race name - like this:

“Just imagine the greatest athlete in the world. The greatest. Now make him six-foot-three, the perfect height. Make him real intelligent and kind. And on top of that, make him the best-lookin’ guy ever to come down the pike. He was all those things as a horse. He isn’t even a horse anymore. He’s a legend.” 

The rumors of Secretariat’s failings as a stud were viciously wrong. He was nearly as successful at breeding as he was on the track. He made a fortune for his owners. But it wasn’t anything about the money that made all who knew him inconsolable when he died. 

They loved Big Red as much as anyone can love anyone else.

Secretariat wasn’t just the greatest race horse ever. He was the greatest athlete ever. Period.