In 896 the Magyars, the last of the migrating tribes to establish a state in Europe, settled in the Carpathian Basin. A century later their king, Stephen I, integrated Transylvania into his Hungarian kingdom. The Hungarians constructed fortresses, founded a Roman Catholic bishopric, and began proselytizing Transylvania's indigenous people. There is little doubt that these included some Romanians who remained faithful to the Eastern Orthodox Church after the East-West Schism. Stephen and his successors recruited foreigners to join the Magyars in settling the region. The foreign settlers included people from as far off as Flanders; Szeklers, a Magyar ethnic group; and even Teutonic Knights returned from Palestine, who founded the town of Brasov before a conflict with the king prompted their departure for the Baltic region in 1225 (see Historical and Geographical Distribution , ch. 2). Hungary's kings reinforced the foreigners' loyalty by granting them land, commercial privileges, and considerable autonomy. Nobility was restricted to Roman Catholics and, while some Romanian noblemen converted to the Roman rite to preserve their privileges, most of the Orthodox Romanians became serfs.

In 1241 the Mongols invaded Transylvania from the north and east over the Carpathians. They routed King Béla IV's forces, laid waste Transylvania and central Hungary, and slew much of the populace. When the Mongols withdrew suddenly in 1242, Béla launched a vigorous reconstruction program. He invited more foreigners to settle Transylvania and other devastated regions of the kingdom, granted loyal noblemen lands, and ordered them to build stone fortresses. Béla's reconstruction effort and the fall of the Árpád Dynasty in 1301 shifted the locus of power in Hungary significantly. The royal fortunes declined, and rival magnates carved out petty kingdoms, expropriated peasant land, and stiffened feudal obligations. Transylvania became virtually autonomous. As early as 1288 Transylvania's noblemen convoked their own assembly, or Diet. Under increasing economic pressure from unrestrained feudal lords and religious pressure from zealous Catholics, many Romanians emigrated from Transylvania eastward and southward over the Carpathians.

Data as of July 1989