Mario Merz, artist: born Milan, Italy 1 January 1925; married (one daughter); died Milan 9 November 2003.

Mario Merz was one of Italy's most prominent post-war artists. He is perhaps now famous for the proliferation of his igloos, which have colonised museums around the world. But this ubiquity threatens to obscure their political origins. His initial rise to prominence came via his association with the highly influential and eclectic Arte Povera group in the late 1960s, which advocated the use of impoverished and often ephemeral materials. Merz's adoption of a distinctive signature style thereafter, manifested in his employment of neon numbers and writing, secured his status over the ensuing three decades.

This fusion of the scientific and artistic found in Merz's work can perhaps be traced back to his parents. The son of an engineer and inventor father who designed for Fiat and a mother who taught music, Merz studied medicine for two years at Turin University. During the Second World War, he was involved with the anti-Fascist group Giustizia e Libertà (Justice and Liberty), leading to his arrest and imprisonment in 1945. He occupied himself by drawing on the humblest materials, including bread and cheese wrappers.

Upon his release, and as a response to his father's pressure to choose a profession, Merz went to Paris and became a truck-driver in Les Halles. Whilst still pursuing his political activities, he also immersed himself in art, ranging from the Louvre to the Informel - the dominant artistic force in France and Italy during this time. After his return to Italy, and throughout the 1950s, Merz worked in opposition to, rather than in accordance with, both the angst of the Informel and the earnest Socialist Realism espoused by his Communist compatriot Renato Guttuso. Instead, he invoked dispassionate images executed in the most impersonal method; utilising industrial materials such as enamel and spray paint.

The epistemological break came in 1966, when Merz moved away from painting, and instead started to penetrate bottles, umbrellas and raincoats with neon tubes to simultaneously imbue them with energy and destroy their functionality. The following year saw the christening of Arte Povera, which included Merz and his wife Marisa, along with fellow poveristi such as Jannis Kounellis and Michelangelo Pistoletto. A riposte to the commercialism and iconism of Pop Art and a rival to American Minimalism, Arte Povera emerged in the ensuring years as the first Italian movement to make an international impact since Futurism.

The tumultuous year of 1968, with its riots, demonstrations and strikes in Italy, France and further afield, marked the adoption of what was to become Merz's signature form - the igloo. The first, Igloo di Giap ("Giap Igloo") bore a phrase inscribed in neon from the North Vietnamese military strategist General Vo Nguyen Giap: "Se il nemico si concentra perde terreno se il disperde perde forza" ("If the enemy masses his forces, he loses ground; if he scatters, he loses strength"). Other works from the same year made explicit reference to the uprisings of May 1968. Che fare? ("What is to be done?") echoed a speech of Lenin's from 1912, while Solitario solidale ("Solitary solidarity") employed words Merz had seen scrawled on a Paris street.

Merz's fascination with the Fibonacci sequence began in 1970. Devised by the medieval monk Leonardo da Pisa in the early 13th century, the mathematical formula followed the strikingly simple proposition that each number cited should equal the sum of the two numbers that preceded it, thus: 1, 1, 2, 3, 5, 8... This numerical series was put to sociological and socialist purposes to photograph and document both factory workers in Naples and customers of the George IV pub in Kentish Town, north London, in his 1972 series A Real Sum Is a Sum of People.

Merz's burgeoning reputation enabled him to transcend whatever poverty was originally implied in his earlier works, in a series of installations in increasingly opulent locations, from the Guggenheim in New York (1971) to the Mole Antonelliana in Turin (1984) and the Salpetrière Hospital in Paris (1987). The one constant was the materials utilised in all these interventions.

The majority of Merz's oeuvre was comprised of three motifs - the igloo, the Fibonacci sequence and his use of neon. Critics who characterised this simplicity as a form of stasis missed the point. Merz was able to orchestrate ever-changing variations on a theme from these origins. As in the Fibonacci series, a simple formula offered an infinite number of possibilities. By 1977, and the emergence of the Transavanguardia in Italy, Merz also returned to painting, now embellishing his canvases with jewel-like neon numbers.

Last month Merz was awarded the Praemium Imperiale in Tokyo along with Bridget Riley, while his influence continues among a new generation of artists. Anya Gallaccio's entry in this year's Turner Prize features the same accumulation of slowly rotting apples that Merz first employed almost 30 years ago.

This April, I went to the opening of what was to be one of Merz's last installations, at the Forum in Rome. In a typically Italian way, dinner took a little too long, and by the time I got there, Merz had gone. All that remained was the glow of his neon spiral coiling around the ancient columns, the Fibonacci sequence unfurling towards infinity.

Nicholas Cullinan