The items include the oldest photograph of the basilica during its early construction phases (1892), a plaster model for a temple window dated around 1900, and a portrait of the architect by Ricard Opisso.
Experts highlight the exceptional value of the collection, which offers a glimpse of the Sagrada Familia before it became a global icon and provides detailed insight into Gaudí's construction processes and working methods.
The photograph, part of an album with 69 images, shows now-vanished construction elements and architectural solutions. The plaster model, from the collection of historian Isidre Puig Boada, is a valuable example of Gaudí's creative process, particularly significant due to the destruction of original material during the Spanish Civil War.
The portrait by Ricard Opisso, a painter and draftsman linked to Gaudí since childhood, depicts the architect focused on the basilica's plans, with a sketch of his ideas floating above his head. Opisso was part of the Els Quatre Gats group.
The pieces are being auctioned separately with starting bids ranging from 5,000 euros for the photograph, 1,000 euros for the portrait, and 12,000 euros for the plaster model.
