Prince Nikolai Sergeyevich Trubetzkoy (Russian: Никола́й Серге́евич Трубецко́й, IPA: [trʊbʲɪtsˈkoj]; 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.