Is it what Crédential?
Credential is your passport of road, it allows you, after having made it plug, either in the churches, or in mow town halls, or in the lists, or or in the tourist offices, to sleep in the lists and to have prices in some secteutrs on presentation of Crédential. At the beginning of Paris it is to Notre Dame, passes by the exit and requires of the guard to return to make plug your crédential.
Its History
Credential had for the pilgrim two function, the first that not to be taken by autoritées for a vagrant (it is also valid nowadays), and to make known itself near the clergy which went park of the pilgrim and to have souvant the bed (it is the also valid one nowadays in the lists)