Few people know .. Here is where William Gibson got his inspiration !

Wintermute was the name of a knight in one of the early Crusades. He was severely retarded, but came from a wealthy family who were underwriting that particular Crusade. His knighthood, of course, was hereditary. His family saw this as an opportunity to rid themselves of an embarassment while doing God's Work. They assigned him twenty squires and servants to make sure he presented himself correctly on the journey. During the long march, the other knights and associated personnel became aware that Wintermute was an idiot savant. He could glance at the stars and instantly state their latitude with a remarkable degree of accuracy. The others, awed, assumed he was touched by God -- a sign that proved the worthiness of their endeavor -- and they trusted him to lead the way without reservation.

Unfortunately, Wintermute was unable to assess longitude and so led the group far to the east,. They ultimately arrived at the shores of the Caspian Sea, which they mistook for the Sea of Galillee. Finding no holy sites at all, much less any infidels, the confused crusaders settled there and formed a small community. Every Sunday night, after Mass, they would ceremonially ask Wintermute to tell them their location, which he would do. The colony eventually died out and this tragic story was almost lost to history.