Original sentence: It is a subject of dispute whether elements of the mixed Daco–Roman population survived in Transylvania through the Dark Ages (becoming the ancestors of modern Romanians) or the first Vlachs appeared in the area in the 13th century after a northward migration from the Balkan Peninsula
Edited sentence: It is a subject of dispute whether elements of the mixed Daco–Roman population survived in Transylvania through the Dark Ages (becoming the ancestors of modern Romanians)