In cosmology, the Deshret was believed to be given by Geb to Horus to rule over Lower Egypt. The pharaohs being the successors of Horus used this crown until the unification of Egypt.
Despite its importance, no Deshret exists as of today probably because it was made of organic material like reeds, cloth or rubber. Some suggests that it was made of copper, thus its color, but these remain to be speculative. It was believed to be passed on from pharaoh to pharaoh. Proof of the existence of the Deshret is seen in the very famous Narmer