Squeezed between the long reigns of his father and son is the important 10-year rule of Stefan Decanski (pr. DE-chan-ski) - a tragic but significant figure of the Nemanjic dynasty. Sent at an early age by his father as a hostage ensuring Tatar neutrality, he managed an escape much later and was granted a traditional appanage in Zeta. Despite his father Milutin's long reign, succession issues were left murky for a long time, exacerbated by the fact that Milutin himself was technically perhaps just a regent for his elder brother, and had at least two male heirs from his four wives. Forced to rebel against his father by an aggressive nobility in 1314, Stefan was defeated, blinded, and exiled, to be pardoned and returned only towards the end of Milutin's rule, in 1320. His father's sudden illness and death the next year triggered the predictable dynastic struggle. But Stefan - his eyesight having been restored, tradition has it, by the miraculous intervention of St. Nicholas - came out assertive and victorious, after a three-year fight.

In terms of foreign policy, notable are Stefan's dealings on the southwestern, Adriatic front, where dynastic struggles and disloyalty of peripheral nobles were opportunistically exploited by the Bosnian ban Stjepan - who annexed the Hum area - as well as the Dubrovnik Republic. Ensuing warfare and diplomacy regained some stability and territory for Stefan in 1328. However, by this time and continuing, the major theater of international affairs for the Nemanjic monarchy lied towards the south and east-facing Bulgaria and Byzantium.

Byzantine internal warfare between the old Andronikos II and his grandson Andronikos III precipitated complicated moves and shifting alliances between the three Balkan players in the late 1320s; the end result was a serious military showdown between Serbia and Bulgaria at the battle of Velbuzd (modern-day Kjustendil) in 1330 - with Byzantium this time wisely on the sidelines. It ended in a major defeat for Bulgarians, their armies, and nobility in disarray and czar Michael II Sisman killed. This effectively ended any larger importance of the Second Bulgarian Empire that had been revived in 1186; for several decades thereafter it remained a loyal Serbian ally, eventually succumbing to the early wave of Ottoman Turk European penetration.

Despite the glory of this victory which echoed considerably in the contemporaneous chronicles, Stefan was to bask in it not for long. Differences between him and his son Dusan came to the fore shortly - whether based on the latter's ambition, succession worries, or perhaps the frustrated war party supporting and prodding him. After a short conflagration, the son was victorious and crowned King; the deposed Stefan was imprisoned and shortly thereafter died under mysterious circumstances.

Stefan's pious demeanor and life of considerable hardship made him a martyr in the eyes of the Church, and he was later canonized; his feast day is Nov. 24 (11 by Julian calendar), and in the gallery of patron saints of Serbian families (Krsna slava) he is also represented. His main endowment is the famous monastery of Visoki Decani, in western Kosovo, dedicated to Ascension of our Lord (completed later by his son Dusan), after which he has been referred to as Decanski.