South America – specifically Brazil, Argentina, Paraguay, Bolivia and Uruguay – has become an increasingly specialised world provider of soybeans. Indeed, over the last two decades, more than 33 million additional hectares of land (roughly a surface area equivalent to that of Vietnam, or to all the arable surface of Ukraine) have been incorporated into soybean production. This land-use change, here referred to as sojización, has brought multiple consequences, ranging from deforestation, soil degradation and water pollution to agribusiness domination, displacement of family farmers and ‘foreignisation’ of land. While the consequences differ from one place to another, sojización has brought dramatic technological, productive and social transformations throughout the region, leading to increased land concentration and land-use intensification. The consequences of this dramatic change have rightfully received much scholarly attention. Less thoroughly addressed, however, is the preceding history that shaped the preconditions for sojización to occur. This chapter fills this gap through a deep "Polanyian" historical exploration of the multiple shifts and continuities that preceded and, indeed, made sojización possible.