The doctrine of an avant-garde group of Spanish poets in the early 1920s, led by Guillermo de Torre. The Grupo Ultra was founded in 1919, issued its Manifesto vertical ultraísta in the following year, and produced a short-lived magazine, Ultra (1920–21). Under the influence of the French poet Stéphane Mallarmé, the Ultraists rejected all previous poetic traditions, and aimed for the creation of a purified poetry liberated from formal, logical, or narrative structures and from human emotional substance (love poetry was firmly repudiated). The Argentine writer Jorge Luis Borges was briefly associated with the group while in Madrid (1919–21), and proclaimed its principles on his return to Buenos Aires, but he later distanced himself from Ultraism and from his early poetry of the 1920s. Ultraism also had the effect of provoking the philosopher Ortega y Gasset into writing La deshumanización del arte (1925), his consideration of the problems of experimental modern art movements.