The history of the Romanian language started in Roman provinces north of the Jireček Line in Classical antiquity but there are 3 main hypothesis around its exact territory: the autochthony thesis (it developed in left-Danube Dacia only), the discontinuation thesis (it developed in right-Danube provinces only), and the “as-well-as” thesis that supports the language development on both sides of the Danube. Between 6th and 8th century AD, following the accumulated tendencies inherited from the vernacular Latin and, to a much smaller degree, the influences from an unidentified substratum, and in the context of a lessened power of the Roman central authority the language evolved into Common Romanian. This proto-language then came into close contact with the Slavic languages and subsequently divided into Aromanian, Megleno-Romanian, Istro-Romanian, and Daco-Romanian. Because of limited attestation between 6th and 16th century, entire stages from its history are reconstructed by researchers, often with proposed relative chronologies and loose limits. Eastern Romance A number of Romance languages were once spoken in Southeastern Europe for centuries, but the Dalmatian branch of this Eastern Romance disappeared centuries ago. Although the surviving Eastern group of Balkan Romance has in the meantime split into four major languages, their common features show that all of them originated from the same proto-language. Romanian, the largest among these languages, is spoken by more than 20 million people, primarily in Romania and Moldova. Aromanian has about 350,000 speakers who mainly live in the mountainous zones of Albania, Greece, and Macedonia. Some thousand people from the wider region of Thessaloniki speak the third language which is known as Megleno-Romanian. The smallest Eastern Romance language, Istro-Romanian is used by fewer than 1,500 speakers in Istria. Substrate in Romanian Little is known of the substratum language but it is generally assumed to be an Indo-European language related to Albanian.