According to the will, the collection was made up of 800 pictures and exhibited for the first time in “Asylum” granted by the Pau city council and reported on by the director of the gallery Eusebio Rey, by the organiser Salvador Cubells and by the president of the Fine Arts Academy of San Fernando. The collection comprised three groups of pictures: first those coming from Charles III's inheritance, which were confiscated from the Prince in 1835 and formed part of the former Museo de la Trinidad; secondly pictures from his exile in Naples; and finally pictures from purchases made in Spain as a result of the seizure of ecclesiastical property ordered by Mendizábal in 1855. The private collection of the painter José Madrazo, an old friend and director of the Prado Museum should be included in this group. After his death, the collection was bought from his heirs by the Prince.
As a result of the Prince's will, the collection was divided up in 1887 amongst his five children and widow. Alfonso de Borbón, the Prince's son, managed to gather together almost the entire original collection by buying the works from the remaining heirs, except for a few works belonging to his brothers Francisco and Pedro which are at present in the Louvre Museum and in Great Britain. When Alfonso died, he was succeeded by his nephew Manfredo de Borbón, the Duke of Hernani, who kept 681 pictures of the original collection up to his death in 1979.
Manfredo de Borbón and Bernaldo de Quiros, Duke of Hernani (1893 – 1979), was the son of the Marquis de Atarfe and Luis Jesus Borbón, the third son of Prince Sebastián Gabriel. After becoming a widow, his mother got married again, to Manuel Méndez de Vigo by whom she had numerous descendants and for which reason the whole family was always known as Méndez de Vigo. In 1931 the proclamation of the Second Republic and the laws to protect the Spanish Historical Heritage qualified the collection as being property of the Spanish Artistic Treasury. In 1936, the Confiscation Committee seized the Duke of Hernani's entire collection and gave it to the Prado Museum. In 1940 the Headquarters General of the National Artistic Heritage Defence Service returned the collection to its owner and since then, different works have been shown in temporary exhibitions.
In 1976, the Spanish Royal family, allegedly aided by the Duke de Hernani's second wife, Teresa Mariategui, and several civil servants, reportedly drew up a plan to get hold of the Duke of Hernani painting and art collection and sell part of it to obtain capital abroad. The plan is said to have consisted in falsifying the succession of the old Duke and at the same time, destroying the documentation of the collection to avoid any claims by the legitimate heirs.