History of the Greek alphabet retained the sound. A symbol based on the left-hand half ( ├ ) of the letter Η was therefore sometimes used to indicate the presence of where necessary, and its absence was indicated by a symbol based on the right half. During the classical period, ΕΙ came to be pronounced and ΟΥ came to be pronounced , Υ having meanwhile moved to . By about 200 BC, a system of diacritical marks was invented, representing the tone accents in use in Ancient Greek. This also helped to indicate the length of the vowels Α, Ι, and Υ in certain cases
History of the Greek alphabet Midas. This link may have facilitated the Greeks "borrowing" their alphabet from the Phrygians because the Phrygian letter shapes are closest to the inscriptions from Aeolis. Some scholars argue for earlier dates: Naveh (1973) for the 11th century BC, Stieglitz (1981) for the 14th century, Bernal (1990) for the 18th–13th century, some for the 9th, but none of these are widely accepted. According to legends recounted by Herodotus, the alphabet was first introduced to Greece by a Phoenician named Cadmus: Herodotus estimates that Cadmus lived sixteen hundred years earlier, or around 2000 BC. He had seen and described the Cadmean