Modern Greek (νέα ελληνικά [ˈnea eliniˈka] or νεοελληνική γλώσσα [neoeliniˈci ˈɣlosa] "Neo-Hellenic", historically and colloquially also known as Ρωμαίικα "Romaic" or "Roman", and Γραικικά "Greek") refers to the dialects and varieties of the Greek language spoken in the modern era.The end of the Medieval Greek period and the beginning of Modern Greek is often symbolically assigned to the fall of the Byzantine Empire in 1453, even though that date marks no clear linguistic boundary and many characteristic modern features of the language arose centuries earlier, between the fourth and the fifteenth centuries AD.During most of the period, the language existed in a situation of diglossia, with regional spoken dialects existing side by side with learned, more archaic written forms, as with the demotic and learned varieties (Dimotiki and Katharevousa) that co-existed throughout much of the 19th and 20th centuries.