In 1798, a French emperor named Napoleon Bonaparte invaded Egypt with grand dreams of conquering the world. Napoleon had a great appreciation for arts and culture, so when he invaded Egypt, he took along a group of soldiers and told them to seize any cultural artifacts for France.
On July 19, 1799, one of these soldiers (Pierre Bouchard) stumbled across a large black basalt slab inscribed with an ancient passage written in three different scripts: Greek, Egyptian hieroglyphics, and Egyptian demotics. When the British defeated Napoleon in 1801, they took possession of the Rosetta Stone and worked for years to decipher the passage.
French egyptologist Jean-Francois Champollion ultimately cracked the code to translate the hieroglyphics, an ancient form of picture writing used in ancient Egypt. Once the Rosetta Stone inscriptions were translated, the language and culture of ancient Egypt was suddenly open to scientists as never before.
Since 1802, the Rosetta Stone has been kept in the British Museum, along with many other artifacts from ancient Egypt. Find out more: http://www.britishmuseum.org/explore/highlights/highlight_objects/aes/t/the_rosetta_stone.aspx