According to the narrator - Geoffrey Chaucer- A GROUP OF PILGRIMS, "sundry folk" arrived at the inn.
Each pilgrim is described in the Prologue of the book. ( A pilgrim is a traveler sho is on a journey to a holy place. In this case, to Canterbury, where the shrine of Thomas Beckett is).
Chaucer describes their condition, their social decree and their array. Among the pilgrims there are a knight, a squire, a cook, a carpenter, a doctor of physic, a wife of Bath, etc.
At the end of the Prologue, the host proposes a story telling contest: each pilgrim will have to tell 2 stories on the way to Canterbury and two on the way back.
That's why the title of the book is the "Canterbury Tales"
