After the conquests of Alexander the Great in the late 4th century BC, a new international dialect known as Koine or Common Greek developed, largely based on Attic Greek, but with influence from other dialects. This dialect slowly replaced most of the older dialects, although the Doric dialect has survived in the Tsakonian language, which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek. By about the 6th century AD, the Koine had slowly metamorphosed into Medieval Greek.