The Importance of the Rosetta Stone
The stone is not extremely important in its own right, however, the message carved into the stone is called a decree. A decree is an official order issued by a legal authority.
This decree was about King Ptolemy V Epiphanes. The specific decree was inscribed into multiple large stone slabs.
These slabs are called stelaes and were put in every temple in Egypt. The slabs state that the priests of a temple in Memphis, Egypt supported the king. The Rosetta Stone is one of these slabs.