At the age of ten, Gudmundur is fascinated by works of art reproduced in a catalog of the Museum of Modern Art of New York.
From September 1949, Erró studied at the Ecole des Beaux-Arts in Reykjavík and was introduced to the technique of cutting papers. He graduated as a professor of art in the spring of 1951.
From 1952, he completed his training at the Oslo Academy of Fine Arts and attended an engraving course at the School of Decorative and Industrial Arts.
In 1954, Erró entered the Academy of Fine Arts in Florence and in 1955 studied the Byzantine mosaics in the School of Mosaic of Ravenna. During the fifties, Erró traveled to Spain, Italy, France and Germany.
In 1958, in Jaffa, Erró executed the drawings and collages of the series "Unmask physicists, empty the laboratories!" (Or "Radioactivity"), titled according to the Parisian surrealist tract of February 18 against the atomic bomb. He settled permanently in Paris.
In 1959, thanks to Jean-Jacques Lebel, Erró met with personalities linked to the surrealist movement. He undertakes a hundred collages on which several paintings are based, in part or in full. It sometimes uses the projector for transfer to the canvas.
In Reykjavík, in 1960, Erró showed his first paintings "Méca-Make-Up" to Dieter Roth which suggests to him to paint in larger ones the remaining collages of the series.
In 1962, Erró diffused in Venice the manifesto "Mecanismo" where appears the notion of "mécacollage". He composed "100 mechanical poems" and the manual "Mecasciences". He presents "Mécacollages" and objects in the exhibition "To ward off the spirit of catastrophe" within the gallery Raymond Cordier in Paris.
In 1964, in New York, Erró renounces definitively to invent personal forms. From images of mass culture, he composed collages which, often enlarged with the help of an episcope or a projector, gave rise to paintings. The following year, he found in Rome postcards representing Pope John XXIII, base for the series of collages "Pope-Art".
In 1966, in New York, Erró created collages and paintings of the Russian-American series "Forty-Seven Years".
In 1967, he composed, in homage to Georges Grosz, the collages of the series "Ecce Homo", painted in 1968. He finds in Cuba, in the catalog of an American painting factory, images of interiors which will enter The composition of the American Interiors (1968).
In 1970, in a castle in the Paris region, Erró found posters of Chinese propaganda that inspired him the series "4 cities" (1972).
In 1975, for the project to rehabilitate the Stucky Mill, launched by the Venice Biennale, he designed 100 collages, some of which were inspired by the building itself and the other designed for interior decoration, Occupation of Venice by Chinese armed forces.
