Greek is the world's oldest continuously documented language, with an unbroken written record spanning approximately 3,400 years. It belongs to its own branch of the Indo-European family — the Hellenic branch — with no living close relative. Ancient Greek was the language of Homer, Plato, and Aristotle, and became the lingua franca of the eastern Mediterranean world following Alexander the Great's conquests. The Greek alphabet, developed around the 9th century BC by adapting the Phoenician script, was the first alphabet to systematically represent vowel sounds, and became the ancestor of the Latin, Cyrillic, and Coptic alphabets. Modern Greek emerged from Koine Greek (the common dialect of the Hellenistic period) through Byzantine Greek, reaching its present form after centuries of diglossia between the archaic Katharevousa and the popular Demotic, which was declared the official standard in 1976.
