Prince Rastko Nemanjić (1174–1235), the youngest son of Grand Prince Stefan Nemanja, later left royal life and took monastic vows under the name Sava. During Sava’s time as monk in Mount Athos, he wrote the Karyes Typicon, which was implicitly the first codification of the Serbian language. The second reform was during the rule of Despot Stefan Lazarević, of which Serbian ortography was known as Resava school.
Before 1400, most Serbian vernaculars had two accents, both with fall intonation—the short one and the long one. That is why they are called “old accents”. By 1500, the old accents moved by one syllable towards the beginning of the word, changing their quality to rising accents. For instance, junâk (hero) became jùnāk. The old accents logically remained only when they were on first syllable. Not all dialects had this evolution; those who had it are called neo-shtokavian. The dispersal center was in eastern Herzegovina. Since the 16th century people had been emigrating from this area. The biggest migrations were to the north, then toward Military Krajina and to the seaside (Dalmatia, Istria, Dubrovnik area, including the islands of Mljet and Šipan). In the 1920s and 1930s the royal government tried to settle people from this poor mountainous area to the Kosovo basin. Vojvodina was settled with inhabitants from this area after WWII.