Aramaic is a Semitic language which was the lingua franca of much of the Near East from the 7th c. BC until the 7th c. AD, when it was largely replaced by Arabic. Classical or Imperial Aramaic was the main language of the Persian, Babylonian and Assyrian empires and spread as far as Greece and the Indus valley.
After Alexander the Great destroyed the Persian Empire, Aramaic ceased to be the official language of any major state, though continued to be spoken widely. It was during this period that Aramaic split into western and eastern dialects.
Alphabet
The Aramaic alphabet was adapted from the Phoenician alphabet during the 8th c. BC and was used to write the Aramaic language until about 600 AD. It was also adapted to write quite a few other languages, and developed into a number of new alphabets, including the Hebrew square script and cursive script, Nabataean, Syriac, Palmyrenean, Mandaic, Sogdian, Mongolian and probably the Old Turkic script.
Resources
Digital Maps of the Ancient World 