Around 2000 BC, along with the first great palaces in Crete a kind of writing appears, bearing a similarity to Egyptian hieroglyphics and deriving from ideograms. The form of hieroglyphics on the Phaestos disc (1700-1600 BC) is the main example of this writing and marks the transition towards linear writing. Linear A writing (1700-1400 BC) is pre-Hellenic and has yet to be deciphered. Linear B is the Mycenaean Greek language used by the Achaeans from 1450 BC onwards. It was deciphered by J. Chadwick and M. Ventris. The Greeks adopted the Phoenician alphabet, to which however they added vowels.