The Rosetta Stone is a large granite slab that was discovered in Egypt in 1799 by French soldiers during the Napoleonic Wars. It is inscribed with a decree issued at Memphis in 196 BC on behalf of King Ptolemy V in three scripts: hieroglyphics (the script used for sacred or formal inscriptions), demotic (the script used for everyday purposes), and ancient Greek.

The significance of the Rosetta Stone lies in the fact that it provided the key to deciphering ancient Egyptian hieroglyphics, which had been a mystery for centuries. The text on the stone was a duplicate of a decree issued by Ptolemy V, and scholars were able to use the known Greek text to help decipher the previously unknown hieroglyphic and demotic scripts. The work was carried out by French linguist Jean-François Champollion in the 1820s, and his success in deciphering the hieroglyphs paved the way for the study of ancient Egyptian language and culture.

The Rosetta Stone is now housed in the British Museum in London, where it is one of the most famous and popular exhibits. It is considered to be one of the most important artifacts in the study of ancient Egypt, and its discovery and decipherment is seen as a landmark achievement in the history of linguistics and archaeology.