The term “bard” is originally of Celtic origin, descended from the Old Celtic “bardos” which in turn produced the Scottish and Irish Gaelic “bard.” This reference means “poet-singer”, which introduced the word into English as a “strolling minstrel” (Ayto 1990).
The Dungeons & Dragons bard is a hodgepodge at least three different kinds of musical singers: the Norse skald, the Celtic bard, and the southern European minstrel. The Celts had a much more organized structure, filling the important role of historian – trained by druids to follow heroes into battle to record their deeds. Minstrels, perhaps the best known bard archetype, were entertainers for nobles in Italy and Germany in the Middle Ages. In France, they were known as Jongleurs, from which we get the term “juggler” and “jester.” Skalds were old Nordic warriors given the honorary position of historian, passing on tales of ancient battles and deeds through an oral tradition. Tolkien copied this style several times throughout The Lord of the Rings trilogy, Bilbo’s chant of Earendil the Mariner being just one example (Schwegman 1976).
In Dungeons & Dragons the bard is a jack-of-all trades, possessing traits of the fighter, thief, and magic-user classes. He also has the ability to charm monsters, can use magical musical instruments more effectively, and possesses the infamous bardic lore, which allows the bard dredge up knowledge about practically anything.
The bard underwent a series of transformation across different editions of Dungeons & Dragons. Its official debut in Advanced Dungeons & Dragons was modified so it was more of a prestige class, requiring advancement in fighter and then thief before joining bard. It wasn’t until 3rd Edition that the bard was restored as a viable choice for beginning characters, only to be excluded from the 4th Edition Player’s Handbook. It was restored in the Player’s Handbook 2.
This description is a rough draft from my upcoming book, The Evolution of Fantasy Role-Playing Games.