The Uprising against Musa Çelebi

In April 1412, an uprising broke out in north-eastern Bulgaria against Musa Çelebi, the youngest son of the Ottoman ruler Bayezid I. In the early fifteenth century, the Ottoman Empire was in a profound crisis, including a civil war for the throne.
After being captured by Timur in 1402, Musa Çelebi was handed over to his brother Mehmed Çelebi in Bursa. In 1409, Musa gained his freedom and, with the help of the Serbian rulers Vuk Lazarević and Stefan Lazarević, attacked his brother Süleyman Çelebi. His campaign was initially successful, but after defeat at Kosmidion in 1409, he temporarily lost Serbian support.
Over the following years, Musa continued his conflict with Süleyman, fighting in various parts of the Balkans. In 1412, Musa gained the upper hand and established control over the Ottoman possessions in the Balkans. The uprising did not last long, however, as Ottoman vassals, including Stefan Lazarević, abandoned him and military operations against him broke out around Pirot.
Musa Çelebi died on 5 July 1413 near the Iskar River at Çamurlu.
 

The uprising against him was suppressed by the Ottomans, leading to the forced displacement of Bulgarians who had taken part in it.