Napoleon's army discovered the Rosetta Stone in 1799. In the early 19th century, Thomas Young, and then Jean-François Champollion, provided the breakthroughs to deciphering it. At the time, ancient Greek was already well-understood by linguists. In 1822, French scholar Jean-Francois Champollion produced the a phonetic alphabet of hieroglyphic characters, leading to the translation of the text and opening the door to a greatly enhanced understanding of ancient Egypt.
The Greek alphabet, descended from the Phoenician alphabet, has been in use since at least the ninth century B.C. It is a precursor to the Latin, or Roman, alphabet, the most widely used alphabet in the world today. Starting from around the time of Homer in 800 B.C., the Greek culture and language gained wide influence through the Classical period and the start of the era of Roman Empire. During the time of the Rosetta Stone, near the end of the Classical period, ancient Greek was the language used by government and royalty in Egypt.
Egyptian hieroglyphics is one of the oldest writing systems in the world. It is a mostly pictorial system, although it contains phonetic elements. Hieroglyphs were in common use during the period 3000 to 1300 B.C. During this time, the standardized form of hieroglyphs changed little. Priests used hieroglyphs to write prayers and religious texts. Governing bodies also used the script to write royal and historical documents. When the Rosetta Stone was deciphered, over 2,600 years of Egyptian texts were made available for translation and research.
Egyptians developed the Demotic script during the Late Egyptian period. It was used prominently during the Ptolomaic period of ancient Egypt, after 303 B.C. When the Rosetta Stone was created, Demotic was losing influence to ancient Greek, as the latter increased in administrative usage. Demotic was used heavily for religious and literary texts. When the Rosetta Stone was deciphered, the Demotic text was decoded before the hieroglyphic text.