Spain is to request the return of Visigoth artefacts given to Nazi Germany to help prove theories about the common 'Aryan' ancestry of Spain and Germany.

Gold and bronze cups, necklaces and human bones excavated from a Visigoth necropolis near Segovia, north of Madrid, were given to Heinrich Himmler by Spain's fascist leader General Francisco Franco after the SS chief visited Madrid in 1940.

The Visigoths were Germanic tribes who conquered swaths of the Iberian between the 5th and 8th centuries before being ousted by the Moors of the Umayyad Caliphate in 711.

Archaeologist Julio Martínez Santa-Olalla, a member of the Franco supporting Falange, wanted to present the items to Himmler as part of his mission to prove that the Visigoth presence in Spain demonstrated that Spaniards shared the same 'Aryan' ancestry as the Germans.

Himmler was obsessed with racial theory, and proving Germans were descended from the ancient Aryan race.

The archaeologist accompanied Himmler on a visit to the Montserrat monastery near Barcelona on his 1940 visit, where the Nazi leader hoped to find the Holy Grail.

For a visit to the Visigoth archaeological site near the village of Castiltierra planned by Himmler, Santa-Olalla reportedly scoured the area for tall blonde locals to be present.

"They searched the region for tall blonde workers so that Himmler could see the Germanic trace," explained Francisco Gracia, professor of prehistory at the University of Barcelona, reported El Pais.

The trip was cancelled due to bad weather, but the artefacts were presented to officials in Himmler's retinue, sent through the diplomatic service to Berlin, and distributed to museum collections in Nuremberg, Cologne and Vienna.

However, now Spain is collecting evidence for submission as part of a formal request for the items from one of the country's most important ancient sites to be returned by the German and Austrian authorities, and be displayed together in Madrid's National Archaeological Museum.

Sergio Vidal, head of medieval antiquities at the National Archaeological Museum, said: "Dozens of pieces were sent to Germany and they never returned. Now we are trying to find evidence to show that the material was sent to Germany on a temporary basis."

However the collection was not well catalogued, so it is expected that Spain will struggle to prove the items belong to Madrid.