Atop thousands of houses in the warm western regions of the United States are roofs that turn the traditional housetop silhouette on its head. Two panels meet in the middle of the roofline and slope upward and outward, like butterfly wings in mid-flap. This similarity gave the "butterfly roof" its name, and it is a distinct feature of post-war American residential and commercial architecture. In Hawaii, Southern California, and other sun-drenched places, the butterfly roofs made way for high windows that let in natural light. Homes topped with butterfly roofs seemed larger and more inviting.

Credit for the butterfly roof design often goes to architect William Krisel. He began building single-family houses with butterfly rooflines for the Alexander Construction Company, a father-son development team, in Palm Springs, California, in 1957. The Alexander Construction Company, mostly using Krisel's designs, built more than 2,500 tract houses in the desert. These houses, and their roofs, shaped the desert community, and soon other architects and developers began building them, toothe popularity of Krisel's Palm Springs work led to commissions building more than 30,000 houses in the Southland from San Diego to the San Fernando Valley.

But the story of Krisel as inventor of the butterfly roof is actually "not true," as Krisel himself notes. While he did make the feature a Southern California mid-century trademark, it was another architect who first developed the butterfly roof. Twenty-eight years before Krisel designed tract houses for the Alexander Construction Company in Palm Springs, Swiss-French architect and Modernist pioneer Le Corbusier first came up with the soaring architectural feature.

Originally born Charles-Édouard Jeanneret-Gris in Switzerland, Le Corbusier moved to France in 1917, gave himself the new moniker, and began associating with singers, sculptors, writers, and other artists. With his minimalist modern architecture, Le Corbusier sought to create a better functioning, more equal society (in fact, Le Corbusier was a supporter of both Communism and Mussolini). His designs put him at the opposite end of the spectrum from traditionalists and from much of the architecture in his adopted country. Le Corbusier was always ahead of his timeparticularly so in 1930, when he designed the butterfly roof for which Krisel would later get much of the credit.

Le Corbusier's first attempt at the butterfly roof took place in Chile, where he was commissioned to build a vacation home in Zapallar for Eugenia Errazuriz, heiress to a Bolivian silver mining fortune and wife of Jose Tomas Errazuriz, whose father and grandfather had both been President of Chile. Eugenia was a grand patroness of the avant-garde; in addition to the modern cliffside summer home she commissioned, Eugenia was a friend to and avid collector of Picasso. Eugenia's taste for Modernism and Minimalism was widely known within her circles. Mutual friends of Eugenia's and Le Corbusier's thought the two to be of one mind; fellow Swiss-French citizen and Modernist writer Blaise Cendrars introduced the two.

The vacation home, Maison Errazuriz, was set to overlook the Pacific Ocean from a remote spot that presented challenges for Le Corbusier. He met them with his trademark mix of organic design and modern innovation. Le Corbusier planned to build with a rustic mix of stone and woodmaterials that were local to the area and would help combat and stabilize the uneven terrain. A combination of fieldstone and large boulders would serve for the floors and exterior, respectively.

Large cut tree trunks were planned for interior support columns. Kenneth Frampton, another Le Corbusier biographer, notes that Maison Errazuriz "gave rise to what would soon become his characteristic neo-vernacular. An expression both archaic and modern."

The other site-specific aspect of the project was, of course, the unique roof of the Maison Errazuriz: a broad, off-center V "resembling two unequal wings of a gigantic bird in flight," writes Weber. Where the two wings met about one-third of the way along the home, a gully formed, from which the large, winged expanses swept upward. The wings were to be covered in Spanish tiles. This striking design was a distinctive departure from the flat roofs that had become characteristic of the 1920s.

Le Corbusier laid out his plans for the Maison Errazuriz in numerous drawings. The grand vacation home for the Chilean heiress would go no further than that, however. Eugenia Errazuriz's lifestyle and patronage of the arts left her bankrupt (even after she sold several of Picasso's works back to him) the year before construction was supposed to start.

Le Corbusier's butterfly roof finally became real just three years later in Karuizawa, Japan. But it was not built by Le Corbusier—the designer was Czech architect Antonin Raymond. Raymond built a nearly identical version of the Maison Errazuriz as a vacation home near Mt. Asama for himself and his wife. "The Raymonds' design borrowed its distinctive butterfly roof and internal ramp circulation," writes Raymond biographers Kurt Helfrich and William Whitaker. Raymond's version of the house also used rustic woods, though in his case, those local to Japan. Chestnut and cedar made up the structural elements of the home. The house in Karuizawa appeared in the July 1934 issue of Architectural Record. It was Raymond's name, not Le Corbusier's, that appeared alongside the dwelling. Le Corbusier's work had been stolen (or so architectural historians believe). The public, however, would never know differently. Publicly, Le Corbusier praised Raymond for his exciting new feature and its rightful place in Japanese design. Raymond collected the immediate acclaim for the avant-garde design of the butterfly roof.

The appeal of the design grew. Modernist architect Marcel Breuer (a disciple of Walter Gropius, the founder of Germany's modern movement, the Bauhaus) appropriated the butterfly roof for America in 1945 with his Geller House in Lawrence, Long Island. Le Corbusier's ideas were clearly ahead of their time: Breuer's Geller House commission was a pre-fabricated design sanctioned by the US government and meant as an experimental dwelling for postwar America.

Breuer's version of the butterfly-roofed house was binuclear. It consisted of two distinct zones—one for living activities and one for sleeping activities—connected by an entrance hall. "Each of the house's bi-nuclear rectangular elements," writes Masello, "is marked by opposing butterfly roof forms that determine, in part, some of the shapes of the windows." Breuer used the butterfly roof to accentuate his focus on the privacy of the postwar family. Just under the sweeping roofline, Breuer placed long, horizontal bands of windows to let in large amounts of natural light without ever exposing the house's inhabitants. Breuer's house may have started off as an experiment for mass production, but it inevitably ended up a singular example of prefabricated modern American design.

Each time an architect deployed the butterfly roof, it was for a single dwelling: a home for an heiress, the Geller family, or a patron of the arts. It wasn't until William Krisel started building the butterfly roof across the Southern California landscape that the high-society feature became attainable for the everyman. Where Le Corbusier failed to build, Raymond succeeded; where Raymond lacked western sensibilities, Breuer succeeded; and where Breuer failed to build for the true American family, Krisel succeeded. Krisel helped define not only a region, but also an era. Though Le Corbusier first thought of the butterfly roof, it was Krisel who became the feature's greatest ambassador.

· Le Corbusier [Curbed]

· Curbed Features archive [Curbed LA]