Taking Mamluks from Sultan of Egypt

[Basterbane]

I was doing little run with The Conqueror achivement. From time to time I looked at claimants to Sultanate of Egypt (in older game found that they sometimes get miaphysite claimants).

Was super lucky this time, Egypt didn't expand beyond one kingdom and someone indeed converted away from Sunni Islam.
At first he was landed so I could not get him to my court. That changed and even with lowered dimplomatic range he was willing to join my court.
Was participating in Crusade at that time, had to disband the levies, land him and declare war.
While I fought for his claim he joined faction. Took a bit after the war for him to get out of it and he let me retract The Mamluk mercenaries without war.

I might still be able to take over Byzantium and get both Mamluks and Varangians, sadly can't ask Pope for invasion CB (my empire is too big, both catholic and of same dynasty).

Some time ago I really wanted to take over Mamluks in Zoroastrian game, and use them together with Immortals. Little did I know that there is need of a DLC to unlock the Holy Order. Would be easier if I had Sword of Islam DLC as well.

Long story short, I have Mamluks as a vassal while being Catholic Emperor of England. They started little over 6000 in size and now are almost OVER 9000! Year is 11xx something. Got the English melting pot event.