Just like the king of the Andals, the Rhoynar and the First Men has his power supported by the faith of the Seven, so did Polish dukes coöperate with the Catholic Church to strengthen their power. And as the popes at the time were really looking forward to freeing the Holy Land from the Saracens, the dukes could help their chances to win the Cracovian throne by participating (or at least by promising to participate) in a crusade. The crusade movement had been only moderately popular in Poland until then, but we know for instance that Henry, one of Lestek's uncles, did go on one, if not two crusades. Did Henry encourage his nephew to take the cross with tales of his overseas exploits? Unlikely, as he had died 20 years before Lestek was born.
What's more, the image of the crusade movement suffered in Lestek's lifetime after the Fourth Crusade had failed to even reach Palestine and settled on plundering the perfectly Christian Constantinople instead. This was followed by a Children's Crusade, which was just as bad terrible an idea as it sounds. But when Pope Innocent III announced a new crusade in 1215, Lestek resolved to enroll anyway. Innocent promised a plenary (full) indulgence to anyone who would join the crusade himself or send an armed delegate and a partial indulgence for financial support. Taking the cross also gave you a kind of immunity, as any attack on a crusader was punishable by excommunication. The pope's protégé in Poland, Archbishop Henry Ketlich of Gnezno, had little trouble inducing a team of young Polish dukes to make a crusader's vow. The team consisted of Lestek and his brother Conrad, as well as their cousins, Casimir of Opole and Vladislav Spitter. Together they formed a coalition of junior dukes put together by Ketlich to wrest control of all Poland from the elder generation of Wrymouth's descendants.
[[File:Pieczęć Leszka I Białego.jpg|thumb|200px|A seal of Lestek the White]]
First of all, what kind of alcoholism makes you drink beer and mead, but stay away from wine? Secondly, how come the pope bought an excuse so flimsy? And does ''corporis gravedine gravis'' really mean "heavy in his body"? This Latin fragment could be also translated as "being full of catarrh" or "suffering from a heavy cold". Anyway, I suspect that Lestek was trying to excuse his failure to join the crusade with some grave illness, and the necessity to replace wine and water in his diet with beer and mead was not necessarily his personal preference, but a medical prescription. Yes, I know, neither a cold nor being overweight would let me get away with not showing up to work, but perhaps medieval attitudes to sick leaves were more relaxed?
It's also possible that the pope was simply being ironicsarcastic. What he meant was perhaps something like, "look at this northern brute who promised to go on a crusade, but now says he doesn't feel like it! The fat drunken sloth who probably can't even live without those barbaric northern drinks like beer and mead!" But if this was the case, then what convinced the pope to forgive Lestek and not excommunicate him after all? Well, what could have worked was what the duke offered as a replacement.
{{cytat