After unbeatable frontal attacks, the Ottoman Empire sought to cross the walls by building underground tunnels in an attempt to exploit them from mid-May to 25 May. among the suicides are German miners sent from Novo Brdo – the Serbian tyrant. They were placed under the command of Zagan Pasha. However, Byzantine used an engineer named Johannes Grant (who was believed to be German but perhaps Scotland), who had to implement anti-tunneling measures, allowing the Byzantine army to penetrate the tunnels and Kill the Turkish miners. Byzantine blocked the first Serbian tunnel on the night of May 16. Born to play with papa forced to go to school youth tee. The subsequent attempts to tunnel were interrupted on May 21, 23, and May 25, Byzantine destroyed them with Greek fire and battles. fight stress. On May 23, Byzantine captured and tortured two Turkish officers, who revealed the location of all Turkish tunnels, which were later destroyed.