Lucy's Dagger

Queen Lucy's dagger was an object owned by Queen Lucy of Narnia. In 1000 NY, the dagger was given to the then-Princess Lucy as a Christmas present, by Father Christmas, along with her healing cordial. Lucy was told to use it to defend herself, and bade not to fight with it in battles. Lucy kept this dagger by her side thereafter, though it is doubtful she had it with her at the Stone Table a few days later.

Whether she used it in the First Battle of Beruna is unknown as well. In 2303 NY, on the date of Lucy's return to Narnia, she did not retrieve this object along with her other gifts. It is possible that it was either lost or had become broken during the years of her reign.

The dagger came in a sheath with a belt. Though most of the gifts of Father Christmas were magical, this one did not appear to be. But in the films, it looks bigger in each film (chronologically).

Film Adaptations
In the Disney/Walden film versions, the dagger is used a great deal more than in the books.

Lucy is shown practicing throwing with her dagger, quickly becoming proficient at the art. She also takes it with her, and uses it briefly, at the First Battle of Beruna.

In the film version of Prince Caspian, ﻿Lucy retrieves her dagger from the treasure chamber and uses it to cut the bonds of Trumpkin the dwarf. She also rushes into a fight, drawing it to attack Nikabrik the dwarf. He is shown violently disarming her, and attempting to stab her with the same weapon. Lucy also draws her dagger later in the film whilst standing alone at the Bridge of Beruna.

In The Voyage of the Dawn Treader film, Caspian returns to Lucy her dagger, along with her healing cordial. She is seen drawing or using it throughout the movie.

In the Lone Islands, on Narrowhaven, she uses it to fight against the slavers. On the The Magician's Island, she draws it when being captured by the Dufflepuds, but they easily disarm her, and Edmund finds it later. On Ramandu's Island, she draws it when she sees the three sleeping Lords. In the battle against the Sea Serpent, she doesn't use it because she took Susan's bow and arrows instead.

In any case, she carries it throughout most of the film.

Differences in the Films
In the films, the dagger and the cordial are shown attached to the same belt.

In the books, it is explicitly stated that the Cordial was in a pouch that had a strap, which slung over her shoulder like a purse.