Uglješa Mrnjavčević

Jovan Uglješa († 1371 ) was the brother of Serbian King Vukašin and despot of Serres.

The earliest mention Uglješas is dated 1346, but as Uglessa baronus, lord of Trebinje in today's Herzegovina, which at that time belonged to the Serbian state of Nemanjic. At his brother's Vukašin the page Uglješa career made ​​at the imperial court of Nemanjic and rose to the voivode. With the slow fragmentation of the Serbian Empire after Stefan Dušan 's death ' could Uglješa, together with Jelena, the widowed wife of Stefan Dušan, established as part of rulers in Macedonia. He took the title of lords of the Serbian lands, to Greece and the coast. In Byzantine sources it is mentioned only as a despot of Serbia. In the letters of the Patriarch of Constantinople Opel, Philotheos Kokkinos, his territory is called in Serres and on the lower reaches of the goiter.

Under the mediation of the patriarch Philotheos, and a coalition against the Ottomans to favor, came under the rule of his and Elena's dioceses, the Stefan Dušan had once deprived the Church of Constantinople Opel, again under the jurisdiction of the Constantinople Patriarchate. In the Battle of Maritsa in 1371 Jovan Uglješa tried to stop his brother Vukašin the advance of the Ottomans; both lost their lives in battle. He was with Jelena, who later became a nun Jefimija, married, not to be confused with the Dowager Empress Jelena.