Which 12th-century poem first mentions the Round Table?

The 12th-century poem that first mentions the Round Table is Wace’s Roman de Brut.

Completed around 1155, the Roman de Brut is a long Norman-French verse history of Britain. Wace adapted Geoffrey of Monmouth’s Latin Historia Regum Britanniae, expanding its account of Arthur and presenting the legendary king to a wider vernacular audience. In Wace’s poem, Arthur establishes a Round Table so that his leading barons cannot quarrel over precedence.

The table’s shape carries an important political and social idea: because it has no head, no knight automatically occupies the highest place. Later Arthurian writers developed this into the ideal of a fellowship whose members were linked by loyalty, courage, and eventually the quest for the Holy Grail.

The Roman de Brut is not the same work as Geoffrey’s Historia Regum Britanniae, Perceval, or Malory’s Le Morte d’Arthur. Those texts helped shape later Arthurian tradition, but Wace’s poem is the earliest literary source normally credited with introducing the Round Table. Wace himself attributed the tradition to Breton stories, so whether he invented it or recorded an existing tale remains debated.