Complex sentence: Narnia is now in the hundredth year of the tyrannical rule of Jadis, who has returned as a powerful sorceress called the White Witch, Jadis has condemned the land to endless winter--but never Christmas--and has turned hundreds of Aslan's followers to stone.
Split into simpler sentences: Narnia is now in the hundredth year of the tyrannical rule of a returning Jadis. Now a powerful sorceress called the White Witch, Jadis has condemned the land to endless winter--but never Christmas--and has turned hundreds of Aslan's followers to stone.