A profound monarchist, he was a close friend and confidant of the heir to the throne of Spain, the Count of Barcelona, who he served as the Head of his Household from 1954 to 1993.

Aspiring to become an engineer was soon frustrated by the outbreak of the Spanish Civil War in 1936, which resulted in his enlistment in the cavalry of the nationalist faction, eventually becoming lieutenant colonel.

Osorio also took part in 1963, 1965, 1966, 1973, when he already had 16 bone screws; in 1974, when he finished in a respectable 8th place; and aged 58 in 1976, breaking 7 ribs and vertebrae, his right wrist and femur as well as suffering a severe concussion that gave him a two-day coma.

As a result, the Jockey Club stewards declined to renew his riding permit and it was widely said that should he continue, "the hospital would run out of screws and the duke out of legs".

He retired leaving behind an extremely popular legacy, particularly in Britain, where he is remembered for his "courageous and injury-defying performances" at Aintree in which he and his horse "Nereo" became fundamental.

"[1] He was born in Madrid, his parents being Miguel Osorio y Martos, 17th Duke of Alburquerque, and Inés Díez de Rivera y Figueroa, daughter of the 5th Count of Almodóvar, who was also a Grandee.

From 1954, and until 1993, he held the position of Head of the House of the Count of Barcelona, and for his service and dedication Juan Carlos I of Spain made him a knight of the Order of the Golden Fleece.

Whether born in Spain or the United Kingdom: tall, thin like an El Greco character, elegant like an English lord, polite, kind and loyal.

Don Beltrán (he could not be called otherwise) Osorio y Díez de Rivera also responded to the image that Montesquieu had of a great lord: «A man who sees the king, speaks with the ministers, has ancestors and properties.