The man is just a fun writer. He summarizes the first three segments thusly:
In Deus Vult! Part I, we reviewed four hundred years of muslim aggression against Christendom, a region known to the muslims by the subtly suggestive name “House of War.”
In Deus Vult! Part II, we encountered the Standard Model of the Crusades as an unprovoked incursion by boorish oafs (as well as oafish boors) into the suave and sophisticated House of Submission. No one thought to ask how all those muslims got all over everywhere in the first place.
In Deus Vult! Part III, we noted that crusading was a crowd-sourced enterprise with voluntary participation. Participants were enticed by promises of suffering, impoverishment, and probable death. Who can resist inveiglement like that? But crusading was conceptualized as an act of charity and in the mental universe of the day, the greater the sacrifice, the greater the merit. Like any vassal, they were pledged to recover their lord’s lost territories. The Lord in this case was Jesus H. Christ himself, and his lands were all the Middle East. This was not then an unrealistic goal: even Egypt was still about 50% Christian, and the lands more recently lost to the Turks were eminently recoverable. In fact, the Byzantines had briefly recovered some of them, only to lose them once more in the disaster following Manzikert. The crusade was less an organized military expedition than it was a joint pilgrimage undertaken by several thousand well-armed knights initially with the purpose of restoring their Greek brothers’ lost territories; then as it built up steam, of making a pilgrimage to Jerusalem as a sort of protest movement.
Problem was, there’ s a whole bunch of muslims sitting on it.
His latest segment is here.