More than 440 foals have been born there since 1992 (the ranch was acquired the year before). A healthy purebred is worth around $40,000 at birth, Mr. De Lara estimated, and its value can increase to more than $100,000 after it receives years of dressage training.First unified as a breed in the 16th century by King Felipe II of Spain, Andalusian horses are known for their elevation, intelligence and long, flowing manes. They are beloved by Spanish royalty, Spanish monks (who are said to have saved them from extinction in the 12th century) and the Spanish military (which took over the official studbooks before handing them over to the Ministry of Agriculture in 2006).

In America, Andalusians are apparently loved most by the Medieval Times shareholders, many of whom are of Spanish heritage and have enthusiastically invested in the breeding program to supply expensive purebred horses for their campy castles.

“Ultimately, the goal is to have all the horses be Andalusians,” Jon Speier, the senior vice president and general manager of the Dallas castle, said. (Currently the Andalusians are used for the procession and dressage portions of the show, and quarter horses are used in the sword battles.)

The horses go from “enjoying the pastures and the oats and having fun here to suddenly performing before thousands of people,” Mr. Speier said.

Through the end of May, Medieval Times has entertained almost 54 million guests — more than 5 million at the 1,000-seat Dallas castle, which opened in 1992. The Dallas castle, like each of the company’s nine North American castles, has its own horse trainer. Teaching the horses the show’s choreography takes up to three years. Once the rigorous training is complete, Mr. De Lara said, “the horse sees the smoke and lights and hears the music, and he knows what to do.”