Which C.S. Lewis book introduced the fictional lion Aslan?

The Lion, the Witch and the Wardrobe introduced Aslan, the great lion in C.S. Lewis’s Chronicles of Narnia.

Published in 1950, the novel follows Peter, Susan, Edmund, and Lucy Pevensie after Lucy discovers a passage from a wardrobe into Narnia. Aslan is the central benevolent figure who opposes the White Witch’s rule.

Although it was the first Narnia book published, it is not the first event in the fictional world’s internal chronology. The Magician’s Nephew, published later, describes Narnia’s creation and Aslan’s role in it. Readers therefore encounter two common ordering systems: publication order and story chronology.

Aslan’s name means “lion” in Turkish. Lewis also associated the character with Christian symbolism, while presenting Narnia as a distinct fantasy world rather than a direct retelling of the Bible.