II . 1344 Death of Amda Syon , Emperor of Ethiopia. 1349 Prince Stephen Dushan of Serbia assumes the title of Tsar (Caesar); principality of Galicia (Halitsh) comes under Polish control. 1352 Death of Ewostatewos (Eusthathius), Ethiopian monk and religious leader. 1353 Death of Sergius and Herman, Abbots of Valaam .