The English pub "or ale-houses, taverns, inns" of the late Middle Ages needed to identify themselves in some way at a time when most people were illiterate.Displaying a name would have been a waste of time when almost no-one could read, so publicans in common with other tradesmen put some kind of visual symbol outside their premises.
It
might have been something as simple as a bush or a crooked piece of wood. Whatever the object, it became the "sign", and people spoke of being at the sign of the Bush, or Crooked Billet, or whatever. They would not have spoken of being at a pub called the Bush or Crooked Billet.
Such sign-language was used on all sides, not just by tavern-keepers. Church congregations, for instance, were taught to recoqnise saints by their traditional symbols. St Peter was always shown holding the keys to heaven, st John held a lamb, and so on. Since many early hospices were
religious establishments, meant to be used by pilgrims and the like, these Christian symbols often became a kind of inn sign. Some of them are still in use today, found in names
like the Cross Keys and The Lamb.
The English pub "or ale-houses, taverns, inns" of the late Middle Ages needed to identify themselves in some way at a time when most people were illiterate.