Charlemagne's most famous sword is called?

Charlemagne’s most famous sword is called Joyeuse.

Joyeuse is the legendary personal sword associated with Charlemagne in medieval literature, especially traditions surrounding the chansons de geste. Its name comes from the French word for “joyous” or “joyful.” In the legends, the sword was extraordinarily powerful and sometimes said to contain a fragment of the Holy Lance in its hilt.

The sword’s fame grew through stories such as the Chanson de Roland, which connected Charlemagne’s weapons and battle campaigns with heroic and religious imagery. Like Roland’s Durendal, Joyeuse belongs partly to the world of medieval epic rather than securely documented biography. There is no conclusive proof that the surviving ceremonial sword was the weapon Charlemagne actually carried.

A sword identified with Joyeuse was used in French royal coronation processions. It was carried before French kings from the coronation of Philip III in 1270 through that of Charles X in 1825. The sword now associated with the tradition is displayed at the Louvre and is a composite object assembled from parts dating to different periods. Curtana and Durendal are separate legendary swords.