 The scale, time and duration of the uprising is not certain.According to some sources, it broke out in 1404, but was quickly crushed by one of Bayezid I's sons, Süleyman, with Wallachia nevertheless retaining Dobruja and Stefan Lazarević extending his realm's territory, whereas Konstantin and Fruzhin's efforts were futile.Others claim that the uprising began in 1408, and Konstantin and Fruzhin managed to regain their domains from the late Bulgarian Empire south of the Danube at least until 1413, when Musa Çelebi, another son of Bayezid, is documented to have "ruined the Bulgarians".