The meaning of Egyptian hieroglyphs remained a mystery until 1799 when Napoleon's soldiers unearthed a dark, damaged rock in the Egyptian coastal town of Rosetta.
Early alphabets that used such shapes allowed more people to read, and let them read faster, eventually replacing cumbersome pictographic writing systems like Egyptian hieroglyphics.
When Emperor Theodosius abolished all non-Christian temples in 391, the use of hieroglyphs virtually ended, with the last known inscription dating a mere 3 years later.