The miracles of Saint Demetrius bring us additional information about the critical position of the city of Thessaloniki, which was surrounded by Slavic tribes. This time we bring an episode about the Slavic siege of Thessaloniki under the leadership of Hacon/Haton in 614-616. It is said that during the time of Bishop John, the Slavs launched another attack on the city. It is interesting that this time we learn the name of the Slavic leader Hacon, who asks the sorcerer to tell him his fate, but when he learns that the chance of victory is small, he decides to attack immediately, hoping for victory. Apart from the name of the Slavic leader, we learn about another tactic of Slavic warfare, which is that the Slavs covered their monoxils (small boats) rawhide, hoping that it would save them from the Thessalonica fire. However, the sorcerer words turned out to be correct. A miracle man appeared to defend his city. He was first noticed on the rampart, and then on the sea; even the Jews in the city saw him (Christians believed that Jews cannot see these miracles).The victory was again in the hands of Thessaloniki, and the Slavic leader Hacon met a terrible fate. They caught him and then stoned him to death.
A new Slavic attack took place in 618. The source now mentions the involvement of the Avars, whose attacks in the first half of the seventh century were very dangerous for Byzantine Empire. It is interesting that the source now mentions many refugees from Thrace and Illyricum who found their salvation, among other things, in the city of Thessaloniki. Also, there is no mention of monoxil in this attack (it is believed that this is due to the previous heavy defeat of the Slavs under Hacon). The writer says that this was the biggest attack that the Slavs, with the support of the Avars, ever carried out. The attack was personally led by the Avar khan. In the end, the city had to yield to the Avars and Slavs and rich gifts were sent to the Khan. This bought peace for a short period of time. The next event that this source brings is the attempt of the Slavs to occupy Thessaloniki during the earthquake that hit the city in 630. The Slavs thought that the city had collapsed and went to occupy it, but when they got closer to the walls, they saw that walls were intact and standing and that the guards were present. Disappointed, the Slavs abandoned their plan.