When Mehmed Al Fatih conquered Bosnia in 1463, 40,000 (in some sourse it’s said 36,000) families accepted Islam in the city of Jajce and it’s surrounding in one day.
It’s important to metion, the it was all kind of structures that accepted Islam. From the respectable and great, from whom are: Tomo Sigismund and princess Katarina, who became Emina. Also the son of the most siginificant lord duke Stjepan, the great misinter Ahmed-pasha Hercegonic, thill ordinary people.
He (Mehmed Al Fatih) said to them: “Ask from me whatever you want” They said: “Take our young men, so they can serve in Istanbul and get to high positions”. He was amazed of that idea.
The reason for the massively accepting of Islam, was that the people where Kristijans. Their believe was similar to Islam, theyt believed in only one God, no son, no trinity.
They were persecuted from the catolics in Italy and Southern France and called heretics. So they found residence in Bosnia, where the Bogumils accepted them.
In the end of 12th century monarch Kulin accepted the Kristijan faith, and more then 10,000 accepted also.
They were bogumils and their believe was dualistic. They believed in to gods. The god of good and the god of darkness, and that there’s a constant fight between them.