Complex sentence: Stephen Tvrtko I (Стефан Твртко; 1338--10 March 1391) was the first of the kings of Bosnia and widely considered one of the country's greatest medieval rulers.
Split into simpler sentences: Stephen Tvrtko I (Стефан Твртко; 1338--10 March 1391) was the first King of Bosnia. He is widely considered one of the country's greatest medieval rulers.