> Arab Egypt had ownership of the rosetta stone and a vast array of hieroglyphs for over a millennia and never understood it, and launched no program to uncover

> Arab Egypt had ownership of the rosetta stone and a vast array of hieroglyphs for over a millennia and never understood it, and launched no program to uncover their secrets. Significant parallel texts were unknown until the rediscovery of the Rosetta Stone in 1799. The Rosetta Stone was only deciphered as quickly as it was because Champollion had studied Coptic, a then-known and later form of the written Egyptian languages in question. If it weren't for Coptic Christians preserving their language, our understanding of Egyptian would probably be 150 years behind where it is now. If significant parallel texts were known in Egypt in 1000 CE, I'd be surprised if the Egyptians themselves wouldn't have cracked it by 1800 CE. Also, Arab scholars did try to decipher hieroglyphs. See Ayub Ibn Maslama, Dhu Al-Nun Al-Misri, Ibn Wahshiyah, and Abu Al-Qasim Al-Iraqi.