Misled by Nicholas of Cologne

We can't say we're utterly convinced as to the verisimilitude of the Children's Crusade. But there is, at the very least, a primary source. And it doesn't mince words:

About the time of Easter and Pentecost,without anyone having preached or called for it and prompted by I know not what spirit, many thousands of boys, ranging in age from six years to full maturity, left the plows or carts which they were driving, the flocks which they were pasturing, and anything else which they were doing...