Koine Greek (UK English , US English , or ; from Koine Greek , "the common dialect"), also known as Alexandrian dialect, common Attic or Hellenistic Greek (Modern Greek , "Hellenistic Koiné", in the sense of "Hellenistic supraregional language"), was the common supra-regional form of Greek spoken and written during Hellenistic and Roman antiquity. It developed through the spread of Greek following the conquests of Alexander the Great in the 4th century BC, and served as the common lingua franca of much of the Mediterranean region and the Middle East during the following centuries. It was based mainly on Attic and related Ionic speech forms, with various admixtures brought about through dialect levelling with other varieties.