Gračanica is a town located in central Kosovo — de-facto independent, partially recognized state. This town of more than 10,000 mostly Serbian people is centered around the Gračanica Monastery, ten kilometers east of Pristina, the capital of Kosovo. The image of this postcard: Fresco of Saint King Milutin, the founder of Gračanica Monastery, originated between 1319 and 1321.
According to Wikipedia, the Gračanica municipality was supposed to become part of the Community of Serb Municipalities after the 2013 Brussels Agreement, however this still hasn’t been implemented yet despite the promises from the Prishtina government. Still, we can see Serbian post, not Kosovar, was used when this postcard was sent: Serbian stamp is used. Also interesting, if I read the postmark correctly, it shows the name of the town in both Serbian and Albanian languages: Gračanica and Graçanicë.