During the Babylonian captivity of the Jews, which began around 600 BCE, the language spoken by the Jews started to change from Hebrew to Aramaic, and Aramaic square script replaced the Paleo-Hebrew alphabet.[2] After the Achaemenid Empire annexed the Neo-Babylonian Empire in 539 BCE, Aramaic became the main language of public life and administration. Darius the Great declared[3] Imperial Aramaic to be the official language of the western half of his empire in 500 BCE, and it is that Imperial Aramaic that forms the basis of Biblical Aramaic.[4]