Euthymius of Tarnovo was a prominent 14th-century Bulgarian patriarch and scholar who served as the head of the Bulgarian Orthodox Church from 1375 to 1393. A central figure of the Second Bulgarian Empire, he established the Tarnovo Literary School and implemented significant orthographic reforms. His linguistic corrections to religious texts influenced the standardized literary languages used across various Slavic Orthodox regions. He is remembered as a defender of asceticism and a highly respected authority within the Eastern Orthodox world.