The Hundred-Year Winter takes place from 900–1000 Narnia time. The White Witch Jadis

White Witch

Jadis is the main antagonist of The Magician's Nephew and of The Lion, the Witch and the Wardrobe in C.S. Lewis' series, The Chronicles of Narnia...

 cast a spell to make it remain winter all year round, which also prevents the appearance of Father Christmas

Father Christmas

Father Christmas is the name used in many English-speaking countries for a figure associated with Christmas. A similar figure with the same name exists in several other countries, including France , Spain , Brazil , Portugal , Italy , Armenia , India...

. However, Aslan

Aslan

Aslan, the "Great Lion," is the central character in The Chronicles of Narnia, a series of seven fantasy novels for children written by C. S. Lewis. He is the eponymous lion of The Lion, the Witch and the Wardrobe, and his role in Narnia is developed throughout the remaining books...

 brings Peter

Peter Pevensie

Peter Pevensie is a major fictional character in the children's fantasy series The Chronicles of Narnia by C. S. Lewis. Peter appears in four of the seven books; as a child and a principal character in The Lion, the Witch and the Wardrobe and Prince Caspian, and as an adult in The Horse and His Boy...

, Susan

Susan Pevensie

Susan Pevensie is a fictional character in C. S. Lewis' Chronicles of Narnia series. Susan is the elder sister and the second eldest Pevensie child. She appears in three of the seven books—as a child in The Lion, the Witch and the Wardrobe and Prince Caspian, and as an adult in The Horse and His Boy...

, Edmund

Edmund Pevensie

Edmund "Ed" Pevensie is a major fictional character in C. S. Lewis's Chronicles of Narnia. He is a principal character in three of the seven books , and a lesser character in two others .In the live-action films, The...

, and Lucy Pevensie

Lucy Pevensie

Lucy Pevensie is a fictional character in C. S. Lewis' The Chronicles of Narnia. She is the youngest of the four Pevensie children, and the first to find the Wardrobe entrance to Narnia in The Lion, the Witch and the Wardrobe. Of all the Pevensie children, Lucy is the closest to Aslan...

 into Narnia to fulfill the "Prophecy of the Four Thrones":

This would put an end to White Witch's plan and her reign and the endless winter would come to an end. (The final days of the Hundred Year Winter occur during The Lion, the Witch, and the Wardrobe.) The Hundred-Year Winter bears strong parallels with the Norse Fimbulwinter

Fimbulwinter

In Norse mythology, Fimbulvetr , commonly rendered in English as Fimbulwinter, is the immediate prelude to the events of Ragnarök.-Summary:...

.