Robot Mountain Benito Cereno has compiled a partial list of the bad-ass weapons of Catholocism, which include Durendal, "which had in its hilt one of St Peter's teeth, St Basil's blood, a hair of St Denis, and a scrap of cloth that belonged to the Virgin Mary."
There was Joyeuse, the sword of Holy Roman Emperor Charlemagne, which was said to contain bits of the Spear of Longinus in its pommel.
Charlemagne's paladin Roland had a sword called Durendal, which had in its hilt one of St Peter's teeth, St Basil's blood, a hair of St Denis, and a scrap of cloth that belonged to the Virgin Mary. It was said to be the sharpest sword that ever existed. (As long as I'm naming swords from the Song of Roland, Ogier the Dane's magic sword was called the Courtain, and Almace was the sword of Turpin, Archbishop of Rheims.)
Saint Ferdinand III of Castile had a legendary sword called Lobera ("the wolf slayer").
There's the sword of Saint Peter, which he used to cut off the ear of a guard who came to arrest Jesus before the crucifixion, but it's legend is not particularly badass, except in some legends it was given to Saint George, which is pretty cool except obviously he killed the dragon with that spear I was talking about a few paragraphs ago.
(via Super Punch)
(Image: Louis XIV (1638 – 1715), Louvre/Wikimedia Commons)