original: The story began as a sequel to Tolkien's earlier, less complex children's fantasy novel The Hobbit (1937), but eventually developed into a much larger work.
simplifications: This story was before the children's  novel The Hobbit (1937). It turned into a much larger work. The Hobbit is the sequel to Tolkien's earlier fantasy novel but eventually developed into something much larger. The story was a sequel to Tolkien's The Hobbit (1937). It developed into a much larger work. The story began as a sequel to Tolkien's earlier, simpler children's fantasy novel The Hobbit (1937). However, it developed into a much larger work. The story began as a sequel to Tolkien's earlier, less complex children's fantasy novel The Hobbit (1937). It became a much larger work. The story began as a sequel to The Hobbit but eventually developed into a much larger work. The story began as a sequel to Toiken's "The Hobbit" of 1937 but eventually developed into a much larger work. The story starts as a follow up to Tolkien's fantasy book, The Hobbit (1937), but soon grew into a much larger work. The story was a sequel to Tolkien's novel The Hobbit (1937), then it turned into something larger. The story began as a remake to Tolkien's earlier, less complex child fantasy novel The Hobbit (1937), but later developed into a much larger work.