I really (really) hate to get drawn into the morass of "someone is wrong on the internet", but
this review of Season Of The Witch was enjoyable enough, and well enough written, for a big factual error to raise hackles up and down my spine like a low-budget CG effect.
There actually *was* a crusade running during the 14th century - in Lithuania. This was all being run under the nominal banner of the Teutonic Knights, which from the shorts and stills from the film it appears that at least Perlman is portraying (he's certainly wearing their livery, even if the rest of the armour and accoutrements are spread across three centuries). I suspect the film would not have made this connection for the audience, and more relevantly would not have cared enough to make the attempt, which is a shame because it's a fragment of history that has largely disappeared from Western memory (although mad eastern European re-enactors are crazy for the period).
There are quite a few records showing that knights from Western Europe would regularly nip off to Lithuania for a summer of beating up the pagans in order to earn enough brownie points to expunge whatever sins they'd accumulated in their home towns. The Teutonic knights themselves degenerated into little more than a mercenary army used by the Holy Roman Empire to beat up Poland once Lithuania had become nominally Christian, and during the 16th century beating up on peasants. They persisted, weirdly, until Bonaparte dissolved the order in 1804, and probably had spent two centuries hanging around in their castles and order houses eating wurst, drinking watery beer and reminiscing about the good old days.