Ptolemaic dynastyThe Ptolemaic dynasty (ˌtɒlɪˈmeɪ.ɪk; Πτολεμαῖοι, Ptolemaioi), also House of Ptolemy, or Lagid dynasty (Λαγίδαι, Lagidae; after Ptolemy I's father, Lagus), was a Macedonian Greek royal dynasty which ruled the Ptolemaic Kingdom in Ancient Egypt during the Hellenistic period. Their rule lasted for 275 years, from 305 to 30 BC. The Ptolemaic was the last dynasty of ancient Egypt. Ptolemy, one of the seven somatophylakes (bodyguard companions), a general and possible half-brother of Alexander the Great, was appointed satrap of Egypt after Alexander's death in 323 BC.
Hellenistic periodIn classical antiquity, the Hellenistic period covers the time in Mediterranean history after Classical Greece, between the death of Alexander the Great in 323 BC to the death of Cleopatra VII (30 BC) followed by the emergence of the Roman Empire, as signified by the Battle of Actium in 31 BC and the conquest of Ptolemaic Egypt the following year. The Ancient Greek word Hellas (Ἑλλάς, Hellás) was gradually recognized as the name for Greece, from which the word Hellenistic was derived.
EuclidEuclid (ˈjuːklɪd; Εὐκλείδης; 300 BC) was an ancient Greek mathematician active as a geometer and logician. Considered the "father of geometry", he is chiefly known for the Elements treatise, which established the foundations of geometry that largely dominated the field until the early 19th century. His system, now referred to as Euclidean geometry, involved new innovations in combination with a synthesis of theories from earlier Greek mathematicians, including Eudoxus of Cnidus, Hippocrates of Chios, Thales and Theaetetus.
