These two mobile sculptures by Alexander Calder were donated by the artist to the Catalan architect Germán Rodríguez Arias (1902–1987), a pioneer of rationalist architecture in Catalonia, founder member of the GATCPAC and a friend of the architect Josep Lluís Sert. It was Sert who introduced Calder to Rodríguez Arias in 1932, while the artist was in Barcelona, invited by Joan Miró.

The works date from a very significant moment in Calder’s creative development. The artist had moved to Paris in 1926, where he met artists from the European avant-garde with whom he established long-standing friendships. Decisive among them were Marcel Duchamp, Jean Arp and Joan Miró. A key influence in the new volumetric abstraction created by Calder was his visit to Piet Mondrian’s studio in October 1930. Months later, he would produce his first mobile sculpture. In 1932, Calder presented his ‘mobiles’, as Duchamp would call them, for the first time. Later on, Arp coined the word ‘stabiles’ for Calder’s floor pieces.