Decree of Canopus
The Decree of Canopus is a bilingual inscription in two languages, and in three scripts. It was written in three writing systems: Egyptian hieroglyphs, Demotic, and Greek, on an ancient Egyptian memorial stone stele, the Stone of Canopus. The inscription is a decree by Egyptian priests honoring Pharaoh Ptolemy III Euergetes; Queen Berenice, his wife; and Princess Berenice in 238 BC.
Importance for the decipherment of hieroglyphs 
This is the earliest of the series of bilingual inscriptions of the "Rosetta Stone Series", the next being the Decree of Memphis, for Ptolemy IV, and the third, final stone, being the Memphis Decree Rosetta Stone, inscribed for Ptolemy V, in 196 BCE. Having a greater number of different hieroglyphs than the Rosetta Stone, the Canopus Stone has proved crucial in deciphering them. Two copies of the stele stones exist, in different line widths. (See Ptolemaic Decrees.)
Contents of the inscription 
The inscription touches on subjects such as military campaigns, famine relief, Egyptian religion and governmental organization in Ptolemaic Egypt. It mentions the king's donations to the temples, his support for the Apis and Mnevis cults, which enjoyed huge success in the Macedonian - Egyptian world, and the return of divine statues which had been carried off by Cambyses. It extols the king's success in quelling insurgencies of native Egyptians, operations referred to as 'keeping the peace.' It reminds the reader that during a year of low inundation, the government had remitted taxes and imported grain from abroad. It inaugurates the most accurate solar calendar known to the ancient world, with 365¼ days per year. It declares the deceased princess Berenike a goddess and creates a cult for her, with women, men, ceremonies, and special 'bread-cakes'. Lastly it orders the decree to be incised in stone or bronze in both hieroglyphs and Greek, and to be publicly displayed in the temples.
Calendar reform 
The traditional Egyptian calendar had 365 days: twelve months of thirty days each and an additional five epagomenal days. According to the reform, the 5–day "Opening of the Year" ceremonies would include an additional 6th day every fourth year. The reason given was that the rise of Sothis advances to another day in every 4 years, so that attaching the beginning of the year to the heliacal rising of the star Sirius would keep the calendar synchronized with the seasons.
This Ptolemaic calendar reform failed, but was finally officially implemented in Egypt by Augustus in 26/25 BCE, now called the Alexandrian calendar, with a sixth epagomenal day occurring for the first time on 29 August 22 BCE. Julius Caesar had earlier implemented a 365¼ day year in Rome in 45 BCE as part of the Julian calendar.
See also 
- Canopus, Egypt
- Decree of Memphis (Ptolemy IV), for Stone #2.
- Intercalation (timekeeping)
- Ptolemaic Decrees
- Rosetta Stone Decree-list of Ptolemy V accomplishments and rewards honored
- Rosetta Stone
- Budge. The Rosetta Stone, E.A.Wallace Budge, (Dover Publications), c 1929, Dover edition(unabridged), 1989. (softcover, ISBN 0-486-26163-8)
- Pfeiffer, Stefan. Das Dekret von Kanopos (238 v. CHR). Munich: K. G. Sauer, 2004.