in all directions, but lost much of its unity. Different dialects emerged in Assyria, Babylonia, the Levant and Egypt. Around 600 BC, Adon, a Canaanite king, used Aramaic to write to an Egyptian Pharaoh. Imperial Aramaic Around 500 BC, following the Achaemenid (Persian) conquest of Mesopotamia under Darius I, Aramaic (as had been used in that region) was adopted by the conquerors as the "vehicle for written communication between the different regions of the vast empire with its different peoples and languages. The use of a single official language, which modern scholarship has dubbed Official Aramaic or Imperial Aramaic, can be assumed to have greatly contributed to the astonishing success of the Achaemenids in holding their far-flung empire together for as long as they did". In 1955, Richard Frye questioned the classification of Imperial Aramaic as an "official language", noting that no surviving edict expressly and unambiguously accorded that status to any particular language. Frye reclassifies Imperial Aramaic as the lingua franca of the Achaemenid territories, suggesting then that the Achaemenid-era use of Aramaic was more pervasive than generally thought. Imperial Aramaic was highly standardised; its orthography was based more on historical roots than any spoken dialect, and the inevitable influence of Persian gave the language a new clarity and robust flexibility. For centuries after the fall of the Achaemenid Empire (in 330 BC), Imperial Aramaic – or a version thereof near enough for it to be recognisable – would remain an influence on the various native Iranian languages. Aramaic script and – as ideograms – Aramaic vocabulary would survive as the essential characteristics of the Pahlavi scripts. One of the largest collections of Imperial Aramaic texts is that of the Persepolis Administrative Archives, found at Persepolis, which number about five hundred. Many of the extant documents witnessing to this form of Aramaic come from Egypt, and Elephantine in particular (see Elephantine papyri). Of them, the best known is the Story of Ahikar, a book of instructive aphorisms quite similar in style to the biblical Book of Proverbs. Consensus regards the Aramaic portion of the Biblical book of Daniel (i.e., 2:4b–7:28) as an example of Imperial (Official) Aramaic. Achaemenid Aramaic is sufficiently uniform that it is often difficult to know where any particular example of the language was written. Only careful examination reveals the occasional loan word from a local language. A group of thirty Aramaic documents from Bactria have