Stefan Konstantin (; c. 1283–1322) was the King of Serbia from 29 October 1321 to the spring of 1322. The younger son of King Stefan Milutin (1282–1321), he initially held the appanage of Zeta (with Zahumlje and Travunia), and was the heir to the Serbian throne after his father had exiled his elder brother Stefan. After his father's death, a throne struggle broke out between Konstantin, Stefan and their cousin Vladislav II, evolving into the two years long civil war. He was killed in the battle fighting his brother, who went on to defeat Vladislav, too, and gained the Serbian throne as Stefan Uroš III, better known as Stefan Dečanski. Life of Konstantin, who may even be canonized in Middle Ages, was obscured even in medieval chronicles while today is almost completely forgotten. Nearly all data on him are approximate and has to be extrapolated from other biographies. Apparently not much valued by his contemporaries, even by his own father who appointed him a successor only when had no other options, he met a cruel death by the hand of his own brother, losing the throne to which he lawfully succeeded. Early life Regarding Konstantin's personal data, the only confirmed information is that he was the son of king Milutin. His mother, birth date or even the birth sequence between him and his brother and sisters are unknown. This is the result of the missing timetable for a string of five marriages king Milutin had, which is among the largest problems in the Serbian medieval biographical research, as Serbian medieval chronologies and genealogies make no mention neither of Milutin's wives nor his daughters. By traditional historiography, Milutin married five times: 1) Jelena, Serbian noblewoman; 2) Helena, Greek noblewoman; 3) Elizabeth, Hungarian princess; 4) Anna, Bulgarian princess; 5) Simonida, Byzantine princess. Aleksa Ivić placed Konstantin as the youngest child of Milutin, while giving birth date of c. 1274 for his brother Stefan Dečanski. This is in line with Stefan Dečanski's marriage date of 1299, or 1296 by the Bulgarian sources, to Bulgarian princess Teodora. Especially taking into the account that some sources claim he was already married previously to an unnamed woman, but the union was childless. Vladimir Ćorović claimed that Konstantin was the older son, while he considered Stefan Dečanski a child of Milutin's fourth wife Anna, who married the king in 1284. As she was only 5 years old