[1] Despite the peace, in the beginning of the 1380s the Ottomans resumed their campaigns and besieged the important city of Sofia which controlled major communication routes to Serbia and Macedonia.
After the futile attempts to storm the city, the Ottoman commander Lala Shahin Pasha considered to abandon the siege.
[1] However, a Bulgarian renegate managed to lure the city governor ban Yanuka out of the fortress to hunt and the Turks captured him.
[2] The city walls were destroyed and an Ottoman garrison was installed.
With the way to the north-west cleared, the Ottomans pressed further and captured Pirot and Niš in 1386, thus wedging between Bulgaria and Serbia.