Pre-Christian Era, Western Europe
If you cross your fingers when making a wish or if you tell a friend, “keep your fingers crossed”, you are partaking on an ancient custom that required the participation of two people, intersecting index fingers.
The popular gesture grew out of the pagan belief that a cross was a symbol of perfect unity; and that its point of intersection marked the dwelling place of beneficent spirits. A wish made on a cross was supposed to be anchored steadfastly at the cross’s intersection until that desire was realized.
Interestingly, the notion of trapping a fantasy until it becomes a reality is found in another ancient European superstition: tying a string around the finger. Today we the label the practice a “memory aid”, a means of “psychological association” in which the string serves merely as a reminder of a task to be performed. To the Celts, the Romans, and the Anglo-Saxons, however, the string was thought to physically prevent the idea from escaping the body.
Originally, in crossing fingers for good lcukk, the index finger of a well-wisher was placed over the index finger of the person expressing the wish, the two fingers forming a cross. While one person wished, the other offered mental support to expedite the desire. As time elapsed, the rigors of the custom eased, so that a person could wish without the assistance of an associate. It sufficed merely to cross the index and the middle fingers to form an X, the Scottish cross of St. Andrew.
Customs once formal, religious, ant ritualistic have a way of evolving with time to become informal, secular, and commonplace. As the ancient “knock oak” custom generalized to “knock wood” to today’s “knock whatever is handy”, so the “crossed fingers” of friends degenerated to a wisher crossing his own fingers and finally to today’s expression “I’ll keep my fingers crossed”, with the well-wisher never actually doing so, and no one expecting him or her to.
Thus, what once was deliberate and symbolic becomes reflexive and insignificant — though not obsolete. The contemporary street custom among young boys of hooking index fingers as a means of agreement on a deal is similar in form and content to the ancient and original crossed fingers friends.
Article taken from PANATI’S EXTRAORDINARY ORIGIN OF EVERYDAY THINGS.