to the southeast to enter Mesopotamia. To the southeast, it is bounded by the ranges that separate it from the Orontes valley in Syria and the Mesopotamian plain. Following the Armenian genocide, Western Armenia was renamed the Eastern Anatolia Region by the newly established Turkish government. In 1941, with the First Geography Congress which divided Turkey into seven geographical regions based on differences in climate and landscape, the eastern provinces of Turkey were placed into the Eastern Anatolia Region, which largely corresponds to the historical region of Western Armenia (named as such after the division of Greater Armenia between the Roman/Byzantine Empire (Western Armenia) and Sassanid Persia (Eastern Armenia) in 387 AD). Vazken Davidian terms the expanded use of "Anatolia" to apply to territory in eastern Turkey that was formerly referred to as Armenia (which had a sizeable Armenian population before the Armenian genocide) an "ahistorical imposition" and notes that a growing body of literature is uncomfortable with referring to the Ottoman East as "Eastern Anatolia". The highest mountain in the Eastern Anatolia Region (also the highest peak in the Armenian Highlands) is Mount Ararat (5123 m). The Euphrates, Araxes, Karasu and Murat rivers connect the Armenian Highlands to the South Caucasus and the Upper Euphrates Valley. Along with the Çoruh, these rivers are the longest in the Eastern Anatolia Region. Etymology The English-language name Anatolia derives from the Greek () meaning "the East" and designating (from a Greek point of view) eastern regions in general. The Greek word refers to the direction where the sun rises, coming from anatello '(Ι) rise up', comparable to terms in other languages such as "levant" from Latin 'to rise', "orient" from Latin 'to arise, to originate', Hebrew mizraḥ 'east' from zaraḥ 'to rise, to shine', Aramaic midnaḥ from denaḥ 'to rise, to shine'. The use of Anatolian designations has varied over time, perhaps originally referring to the Aeolian, Ionian and Dorian colonies situated along the eastern coasts of the Aegean Sea, but also encompassing eastern regions in general. Such use of Anatolian designations was employed during the reign of Roman Emperor Diocletian (), who created the Diocese of the East, known in Greek as the Eastern Diocese, but completely unrelated to the regions of Asia Minor. In their widest territorial scope, Anatolian designations were employed during the reign of Roman Emperor Constantine I (306–337), who created the Praetorian prefecture of the East, known