The HellenisticPtolemaic dynasty, which ruled Egypt from 305 BC to 30 BC, issued these series of decrees over the course of their reign. The Rosetta Stone is a well-known example of one of the decrees.
There are approximately two copies of the Stone of Canopus, two of the Memphis Stele (one imperfect) and two and a half copies of the text of the Rosetta Stone, including the Nubayrah Stele and a pyramid wall inscription with "edits", or scene replacements, completed by subsequent scribes.
Rosetta Stone detail
The three Decrees, the three-stone series
Multiple copies of the stones were erected in multiple temple courtyards, as specified in the text of the decrees.
stone 1: Stele No. 1, found 1902, hieroglyphs, demotic, and Greek, dark granite.
stone 2: Pithom Stele, No. II, found 1923, hieroglyphs (front), 42 lines Demotic (back), virtually complete providing almost total translation, and Greek (side), sandstone.
stone 1: Rosetta Stone, "Stele of Rosetta", found 1799, (remaining) hieroglyphs, 14 lines, 32 lines Demotic, 54 lines Greek 'capitals', dark granite-(granodiorite).
stone 2: Stele of Nubayrah, found early 1880's, hieroglyphs, lines 1-27 used to complete missing Rosetta Stone lines, demotic, Greek capitals, limestone.
site 3: the Temple of Philae, inscribed hieroglyphs, for Decree of Memphis (Ptolemy V), on walls, also overwritten, by scenes, and figures of humans/gods.
Totals: 6 stones, or stelae, 1 partial, and 1 temple wall inscription writing.