How long was the rule of the dynasty that was active when the Rosetta Stone was inscribed?
Ptolemaic dynasty The Ptolemaic dynasty (Ancient Greek: Πτολεμαῖοι , "Ptolemaioi"), sometimes also known as the Lagids or Lagidae (Ancient Greek: Λαγίδαι , "Lagidai", after Lagus, Ptolemy I's father), was a Macedonian Greek royal family, which ruled the Ptolemaic Kingdom in Egypt during the Hellenistic period. Their rule lasted for 275 years, from 305 to 30 BC. They were the last dynasty of ancient Egypt.
Line of succession to the former Egyptian throne Under the Muhammad Ali dynasty, the line of succession to the former Egyptian throne was subject to a number of changes during its history. From its founding in 1805 until 1866, the dynasty followed the imperial Ottoman practice of agnatic seniority, whereby the eldest male in any generation would succeed to the throne. In 1866, however, the then Khedive of Egypt Isma'il Pasha obtained a "firman" from the Ottoman Emperor which restricted the succession to the male-line descendants of Isma'il Pasha. The resulting succession remained in force until the abolition of the Egyptian monarchy in 1953, following the 1952 Egyptian Revolution.