Prince Nikolai Sergeyevich Trubetzkoy (; 16 April 1890 – 25 June 1938) was a Russian linguist and historian whose teachings formed a nucleus of the Prague School of structural linguistics. He is widely considered to be the founder of morphophonology. He was also associated with the Russian Eurasianists. Life and career Trubetzkoy was born into privilege. His father, Sergei Nikolaevich Trubetskoy, came from a Lithuanian Gediminid princely family. In 1908, he enrolled at the Moscow University. While spending some time at the University of Leipzig, Trubetzkoy was taught by August Leskien, a pioneer of research into sound laws. After he graduated from the Moscow University (1913), Trubetzkoy delivered lectures there until the Russian Revolution, when he moved first to the University of Rostov-on-Don, then to the University of Sofia (1920–1922) and finally took the chair of Professor of Slavic Philology at the University of Vienna (1922-1938). Trubetzkoy was involved with the Eurasianist movement and became one of their leading theorists and political leaders. After the emergence of "left Eurasianism" in Paris, where some of the movement's leaders became pro-Soviet, Trubetzkoy who was a staunch anti-communist heavily criticised them and eventually broke with the Eurasianist movement. He died from a heart attack attributed to Nazi persecution after he had published an article that was highly critical of Hitler's theories. Trubetzkoy's chief contributions to linguistics lie in the domain of phonology, particularly in the analyses of the phonological systems of individual languages and in the search for general and universal phonological laws. His magnum opus, Grundzüge der Phonologie (Principles of Phonology) was issued posthumously in which he defined the phoneme as the smallest distinctive unit within the structure of a given language. It was crucial in establishing phonology as a discipline separate from phonetics. Trubetzkoy also wrote as a literary critic. In Writings on Literature, a brief collection of translated articles, he analyzed Russian literature beginning with the Old Russian epic The Tale of Igor's Campaign and proceeding to 19th-century Russian poetry and Dostoevsky. It is sometimes hard to distinguish Trubetzkoy's views from those of his friend Roman Jakobson, who should be credited with spreading the Prague School views on phonology after Trubetzkoy's death. As structuralist In his biography of the mathematical collective Nicolas Bourbaki, Amir Aczel described Trubetzkoy as a pioneer in structuralism, an interdisciplinary outgrowth of structural linguistics that would be applied in mathematics by the Bourbaki group, as in