The road exists because of a claim about a grave. In the early ninth century a burial in a field in Galicia was identified as that of James the Great, the apostle, on the authority of the local bishop Theodomir, whose own tombstone was found on the site in the nineteenth century and is one of the few hard objects in the story. The legend that carries the identification is the translatio: that after the apostle's execution in Judaea his disciples carried the body by sea to the far end of the known world.
The scallop shell attached itself to the pilgrimage early and its origin is not settled. It is native to the Galician coast, it was sold at Santiago as proof of arrival, and it works as a scoop for water. Whatever the reason, by the twelfth century it was the badge of the Santiago pilgrim specifically, in a period when different shrines had distinct badges, and it is now the waymark as well as the emblem: a stylised shell on a blue ground marks the routes across several countries.
The administrative apparatus is medieval in principle and modern in operation. The credencial is stamped at albergues, churches and bars along the way, and on presentation at the Pilgrim's Office in Santiago, showing the last hundred kilometres walked or two hundred cycled, it earns the compostela, a certificate issued in Latin with the pilgrim's name Latinised. The office asks the motive for walking and publishes the breakdown.
Two further institutions belong to the destination rather than the road. The botafumeiro, the great censer swung across the transept by a team of tiraboleiros, and the Holy Year, declared whenever 25 July falls on a Sunday, when the cathedral's holy door is opened.