Black muslim man uses taqiyya on you, it's kinda effective.
(realistically any promotion of islam would have raised enough eyebrows to lead to capital punishment during this time but this game is made by subversives like him)
Vavra tried to justify it with King Sigismund personally recruiting him or something.
Sigismund as an historical figure concerning religion is very interwoven with the Hussite Reformation.
Short Background, Jan Hus was a czech Preacher and made some demands of Rome that would later be echoed in the more successful Reformation of Luther, Calvin and Zwingli.
At that time, one of the most important concils of catholic history happened in the south-german city of Konstanz.
The concil was huge, took several years and led to reforms that still shape the church.
One of the main issues was the schism and the challenge of local heresies.
They summoned Jan Hus to defend himself and his teachings, which he denied at first, fearing for his life.
Sigismund promised him safe conduct if he came, and he agreed.
Well, the bishops arrested, tried and burned Hus at the pyre while Sigismund did nothing.
This was of course a complex situation for him, and you could take the voucher of safe conduct as an act of greater tolerance than from the establishment church-princes, but even if he was honest and not just a rat, he roached out in the end.
So I would find it kind of doubtful that he would protect some uppity nigger spousing the virtues of Islam in his camp.