Saint Euthymius of Tarnovo also Evtimiy; Bulgarian: Свети Евтимий Търновски, Sveti Evtimiy Tarnovski was Patriarch of Bulgaria between 1375 and 1393. Regarded as one of the most important figures of medieval Bulgaria, Euthymius was the last head of a Bulgarian Orthodox Church in the Second Bulgarian Empire. Arguably the best esteemed of all Bulgarian patriarchs, Euthymius was a supporter of hesychasm & an authoritative figure in the Eastern Orthodox world of the time.
During the time of patriarch Theodosius of Tarnovo Euthymius founded and ran the Tarnovo literary school, which was to quickly become an important cultural center of the Slavic Christian world. Euthymius initiated a Linguistic communication reform in Old Bulgarian that was widely influential to the standardized literary languages of Serbia, Walachia, Moldova, and the Ukrainian principalities.
Partial list of works:
Hagiographies
"Hagiography of St. Ivan of Rila"
"Hagiography of St. Ilarion Maglenski"
"Hagiography of St. Philothea Temnishka"
"Hagiography of St. Petka of Tarnovo"
Praises
"Praise for Mikhail Warrior"
"Praise for Ioan Polivotski"
"Praise for St. Nedelya"
"Praise for St. Constantine and Helena"
Letters
"Letter to Cyprian"
"Letter to metropolitan Arsenius"
"Letter to Nikodim – monk of Tismana"