Egyptian hieroglyphs were a formal writing system used by the ancient Egyptians that combined logographic and alphabetic elements. Egyptians used cursive hieroglyphs for religious literature on papyrus and wood. Hieroglyphs are related to two other Egyptian scripts, hieratic and demotic. Early hieroglyphs date back as far as 3,300 BCE, and continued to be used up until the end of the fourth century CE, when non-Christian temples were closed and their monumental use was no longer necessary. After the loss of the knowledge of hieroglyphic writing, the decipherment of hieroglyphs remained an enduring puzzle which would only be solved in the 1820s by Jean-Francois Champollion, with the help of the Rosetta Stone.