In 1943 he purchased Rancune, who had won several times on the racetrack and who came from an excellent family. Her dam, Rockella, is by Bishop’s Rock, a son of Teddy who carries the great jumping blood of Bay Ronald on his dam line.

At stud, Rancune produced only winners, three of them by the stallion, Foxlight.

Foxlight was the star of the famed French stallion station, Haras du Pin. A very ‘chic’ chestnut roan, he had won and placed in classic races before being retired to stud, where he was immediately successful.

Bred to Foxlight, Rancune produced Rantzau in 1946. Rantzau was a solid performer on the track, rated three of his three-year-old generation, with 9 races between 2,000 and 3,000 metres. He won two and was placed five times. He was purchased by Marcel Boussac at the end of his 3-year-old season, and sold to the National Stud. On January 5th, 1951, he arrived at Saint-Lo in 20 years of breeding, he covered 772 mares, for an average of 38 a year.

By 1958, Rantzau was ranked 17th on the list of top showjumping sires, by 1962, he had moved to 11th spot, and by 1963, he was 5th behind Foudroyant II, Furioso, Nithard and Brûle Tout. Next year, he had moved into 2nd place behind Furioso, thanks in part to Labrador C, who was now ranked 3rd amongst the aged horses, behind the Olympic gold medallist, Lutteur B (Furioso).

Rantzau’s fame was spreading, Medrano was winning for Holland, and a Thoroughbred, Cour d’Appel (Foxlight out of a daughter of Cor de Chasse) won for Spain at the CSIs of Madrid, Barcelona and Biarritz. Holland and Switzerland were buying Rantzaus. The following year Labrador C’s full-brother, Osiris C is third on the aged standings, just in front of Labrador C, with Luxeuse B in 12th. Rantzau is still in no 2 position on the rankings. Internationally, Nageur (out of Harmonie by Beau Reve) had wins in Lisbon for Portugal, and Pascha du Bourg won an Italian CSI for Spain.

1966 and it is more of the same in France, and he holds second, while internationally, the five (!) year old Radar II is winning CSIs for Italy with the famous Piero d’Inzeo, Medrano is starring for Holland, Nageur for Portugal, and Pascha du Bourg for Spain. Rantzau holds his 2nd spot in 1967, 68 and 69.

In 1970 the rankings are upgraded and the standings for the ‘best sires of dams’ are published for the first time. Rantzau is ranked 3rd of the sires of winners, behind Ibrahim and Furioso. Finally in 1971, Rantzau makes it to the top, ranked in front of Ibrahim and Furioso, thanks to the now 16-year-old Labrador C, along with Roi du Manoir, Osiris C, Prince Royal, Sire du Logis, Amour de Juilley, etc.

Rantzau is now ranked the 5th best sire of Eventers thanks largely to Quolibet Z and Unic F. The following year he holds onto top spot and interestingly for the future his son, Starter (dam sire of Baloubet du Rouet) is moving up on the stallion rankings, 67th thanks to the performance of Beau Fixe in the 5 year olds. In 1973, Rantzau surrenders number one to Ibrahim, but despite that fact that he has been dead for two years, the Thoroughbred continues to hold his spot – and even in 1980, he is in 4th place behind Uriel, Almé and Nankin. His son, Starter has moved up 13th, Kalmiste is 31st (and 6th of eventing sires), Quelqu’un is 78th, Venutard is 8th of the dressage stallions.

In 1981, ten years after he died, Rantzau finally made it to number one on the Sire of Dams rankings. Of his sons in France, Starter moved into the top ten in 1985, and headed the rankings in 1988-89-91-93, 4th in 1994 and 6th in 1996.

In Europe, Cor de la Bryère, born in 1968 out of a mare by the Furioso xx son, Lurioso, has without doubt been the most influential son of Rantzau, establishing one of the two mighty C lines that dominate Holstein – and jumping – breeding to this day.