The fictional family who enter Narnia in C.S. Lewis’s first-published Narnia book are the Pevensies.
Peter, Susan, Edmund, and Lucy Pevensie are the four siblings at the center of The Lion, the Witch and the Wardrobe. They discover Narnia through a wardrobe while staying in the English countryside during the Second World War. Each sibling responds differently to the strange world, especially after Edmund encounters the White Witch.
The Pevensies return in later Narnia books, although not all four appear in every volume. Peter and Susan are especially prominent in the first story, while Lucy and Edmund continue to appear in several later adventures. Their family name distinguishes them from other recurring children, including Eustace Scrubb and Jill Pole.
The Pevensies are not the first humans in Narnia according to the series’ internal chronology. The Magician’s Nephew, published later, depicts Narnia’s creation and introduces other human visitors. In publication order, however, the Pevensies provide the reader’s first major entrance into Lewis’s magical world.