Although Le Corbusier was a Classical regionalist during his formative years in La Chaux-de-Fonds, in Paris he formulated and applied Purism, the universal white machine aesthetic, until he designed Villa Savoye in 1929. He then unexpectedly moved from Purism to a rough, regionally-orientated approach that was often based on vernacular forms. Applying contemporary criteria to a typological assessment, this study investigates the period 1917-1930 to determine the extent of his regional interest, if any, during that time, in order to understand his dramatic shift in architectural expression. It is concluded that Le Corbusier never abandoned regionalism, but applied it in very discreet and sometimes tentative ways. By 1929, however, he had mastered a mature regionalist method with a distinct preference for vernacular forms.
