In Celtic cultures, a bard is an oral repository and professional story teller, verse-maker, music composer, oral historian and genealogist, employed by a patron (such as a monarch or chieftain) to commemorate one or more of the patron's ancestors and to praise the patron's own activities. With the decline of a living bardic tradition in the modern period, the term has loosened to mean a generic minstrel or author (especially a famous one).
https://en.wikipedia.org/wiki/Bard