The first major sire of the line in the United States was Young Emperor, a son of Grey Sovereign and former good British two-year-old. Although well forgotten by history, he left a mark in the United States with his granddaughters Great Lady M and Sookera. The former was a multiple stakes winner and dam of the champion Lady's Secret. Sookera won the Cheveley Park Stakes and became a real foundation broodmare for the Juddmonte Farms. Her family includes Leroidesanimaux, Dansili, and Champs Elysees, as well as many famous female members of the great clan of Hasili.
Caro arrived in 1977, when he had only two crops of three-year-olds on the racetrack, and died in 1989. This branch of the line is still quite young, which is also apparent when considering only his grandsons at stud. Also, the line's members were never numerous, although it has a steady success since the 1990s. In the 2010s, the branch received a new impulse with success of Uncle Mo. The scheme is very short, but it will be interesting to observe its future development.