What are the domestic consequences of symbolic conflict resolution? We isolate the effect of symbolic conflict by looking into a dispute with no material stakes (for one side), but high symbolic ones: the Prespa Agreement, which put an end to the dispute on the official name of FYROM (henceforth North Macedonia). Greek nationals opposed this name because the Macedonian heritage is central to their national identity. Based on social identity theory, we expect this threat to the group's distinctiveness to increase Greek ingroupism. Using an original dataset of flags displayed in the façade of buildings in Athens and Thessaloniki, which we compare to Lisbon (control group), we find an increase in national flags in the two Greek cities after the Agreement. The effect is most remarkable in Thessaloniki (capital of Greek Macedonia), where the identity threat was stronger. We also find that the treaty increased radical right vote in Greek Macedonia.