Murglais, Murgleis or Murgleys, (possibly "Death brand") is the sword of Ganelon, a traitorous French (Frankish) count and to the titular hero of the epic La chanson de Roland (The Song of Roland).
According to the French version, its "golden pommel ()" held some kind of a holy "relic".
In the Middle High German adaptation (Konrad der Pfaffe's Rolandslied) the sword is called Mulagir, touted to be the "best short sword in all of France", described as having a carbuncle on its pommel that shone bright by night, forged by a smith named Madelger in Regensburg. It had belonged to Naimes who brought it out of his fiefdom of Bavaria and presented it to Karl(Charlemagne), but unfortunately Ganelon took possession of it and carried it to the Saracen side.
(vv. 346, 607 Oxford ms.), Franco-Italian:
In editions: Morglès (Moncrieff tr.).
Dorothy L. Sayers, a translator of The Song of Roland suggests the sword means "Death brand" (cf. below). Belgian scholar Rita Lejeune gave the meaning "Moorish sword", but Arabist James A. Bellamy proposed the Arabic etymology mÃÂriq þalyas meaning "valiant piercer".
At least three swords bearing the similar name Murglaie occur in other chansons de geste.
Note that "Morglay" has been given the etymology morte "death" + "glaive" coinciding with the conjectural meaning of "Death brand" for Ganelon's sword, proposed by Sayers.