Baudoin the Dragonslayer

Baudoin the Dragonslayer was a King of Bretonnia and thus one of the mighty Grail Knights.

History
The most notable act of King Baudoin's rule occurred in the year 1245 IC, when he fought and slew the ferocious Dragon, Mergaste. A great fresco in the cathedral of Bastonne commemorated the heroic deed, and Baudoin was known thereafter as the "Dragonslayer."

Even after a millenia had passed, the King's great victory would remain a fabled part of Bretonnian history.

Source

 * Guardians of the Forest (Novel), by Graham McNeill