The horse died due to cardiac failure on March 21, according to a statement.
“The incident took place in the morning whilst the horse was being exercised prior to rehearsals.
The trainer was not in costume and filming had yet to commence.

The cavalry of Numenor arrives in ‘The Lord of the Rings: The Rings of Power’.Prime Video
Both a veterinarian and a representative of the American Humane Association were present at the time.”
An “independent necropsy” was conducted and found the horse died due to cardiac failure.
This is said to be the first horse fatality in the company’s 50-year history.
While the death of an animal on set is rare, it’s not unheard of.
In 2012, HBO’s horse-racing seriesLuckwas canceledafter three horses died during production.