of Arameans in western Syria, and persisted in Mount Lebanon until as late as the 17th century. The term "Old Aramaic" is used to describe the varieties of the language from its first known use, until the point roughly marked by the rise of the Sasanian Empire (224 AD), dominating the influential, eastern dialect region. As such, the term covers over thirteen centuries of the development of Aramaic. This vast time span includes all Aramaic that is now effectively extinct. Regarding the earliest forms, Beyer suggests that written Aramaic probably dates from the 11th century BCE, as it is established by the 10th century, to which he dates the oldest inscriptions of northern Syria. Heinrichs uses the less controversial date of the 9th century, for which there is clear and widespread attestation. The central phase in the development of Old Aramaic was its official use by the Neo-Assyrian Empire (911-608 BC), Neo-Babylonian Empire (620-539 BC) and Achaemenid Empire (500–330 BC). The period before this, dubbed "Ancient Aramaic", saw the development of the language from being spoken in Aramaean city-states to become a major means of communication in diplomacy and trade throughout Mesopotamia, the Levant and Egypt. After the fall of the Achaemenid Empire, local vernaculars became increasingly prominent, fanning the divergence of an Aramaic dialect continuum and the development of differing written standards. Ancient Aramaic "Ancient Aramaic" refers to the earliest known period of the language, from its origin until it becomes the lingua franca of the Fertile Crescent. It was the language of the Aramean city-states of Damascus, Hamath and Arpad. There are inscriptions that evidence the earliest use of the language, dating from the 10th century BC. These inscriptions are mostly diplomatic documents between Aramaean city-states. The alphabet of Aramaic at this early period seems to be based on the Phoenician alphabet, and there is a unity in the written language. It seems that, in time, a more refined alphabet, suited to the needs of the language, began to develop from this in the eastern regions of Aram. Due to increasing Aramean migration eastward, the Western periphery of Assyria became bilingual in Akkadian and Aramean at least as early as the mid-9th century BC. As the Neo-Assyrian Empire conquered Aramean lands west of the Euphrates, Tiglath-Pileser III made Aramaic the Empire's second official language, and it eventually supplanted Akkadian completely. From 700 BC, the language began to spread