A few years after Jesus was crucified. St. James sailed to Galicia and began ministering to the pagans he found there. He was not successful in converting the pagans to christianity and so returned to Jerusalem where he was beheaded by Herold. His followers took his body and buried it in n Galicia. Fast forward to AD813; a shepherd named Pelayo saw a bright light over a field in Galicia. Speculation raged that the stars shone on an important burial site. The Bishop of Padron claimed it to be the burial site of St. James. And there we have it "the way to St. James of the the field of stars" ( My spanish is very dodgy but my deductive reasoning)
El Camino: the way
Santiago: St. James (San Iago)
Compos: Field
Stela: Stars
The claim by the Bishop of Padron was in sync with the "Spanish expulsion of the Moors and Islam " from the Iberian peninsula and so met with insititutional support by the church and royalty. The way of St. James then gained in popularity and importance as Bishops, Popes and Royalty made the pilgrimage. Miracles were reported all along the route. At one time, El Camino de Santiago was more popular than the pilgrimage to Jerusalem. As the pilgrimage gained in popularity so did the embellishments along the route. The concentration of spectacular churches, monastaries is what attracted UNESCO to make the pilgrimage a world heritage site in 1987. Today it is estimated that as many as 130,000 make the pilgrimage each year. As 2010 is a holy year (July 25th falls on a Sunday, this number will be far exceeded).
The Credencial, Pilgrim Record or Pilgrim Passport is a distant successor to the safe-conducts issued to medieval pilgrims. The document is printed and issued by the cathedral authorities in Santiago, and made available to bona fide pilgrims at points along the route. 
Trivial Pursuit: The Shell logo from the Oil company shell is the St. James scallop adopted to the family's coat of arms after a pilgrimage to Santiago!! When the Royal Dutch Petroleum Company and “Shell” Transport and Trading merged in 1907 it was the latter’s brand name and symbol which then became the short form name (“Shell”) and the visible emblem (the “Pecten”) of the new Royal Dutch/Shell Group. And so it has remained ever since.
