The Orthodox churches of the former principalities, the Metropolitan of Ungro-Wallachia and the Metropolitan of Moldavia, merged to form the Romanian Orthodox Church.
In 1864, the Romanian Orthodox Church was proclaimed independent, but the Ecumenical Patriarch pronounced the new ecclesiastic regime contrary to the holy canons.
In the 1330s, according to a papal tithe-register, the average ratio of villages with Catholic parishes was around forty percent in the entire kingdom, but in the territory of modern Romania there was a Catholic church in 954 settlements out of 21 settlements.
The Diet recognized the existence of two distinct Protestant churches in 1564 after the Saxon and Hungarian clergy had failed to agree on the contested points of theology, such as the nature of communion services.
Orthodoxy was for centuries only tolerated in the regions west of the Carpathians where Roman Catholic dioceses were established within the Kingdom of Hungary in the 11th century.
In these territories, transformed into the Principality of Transylvania in the 16th century, four "received religions" – Calvinism, Catholicism, Lutheranism, and Unitarianism – were granted a privileged status.
A gem representing the Good Shepherd was found at Potaissa.From the 15th century the four Eastern patriarchs and several monastic institutions in the Ottoman Empire also received landed properties and other sources of income, such as mills, in the two principalities.Wallachia in particular became a leading center of the Orthodox world, which was demonstrated by the consecration of the cathedral of Curtea de Argeș in 1517 in the presence of the Ecumenical Patriarch and the Protos of Mount Athos.Evidence of Christian communities has been found in the territory of modern Romania at over a hundred archaeological sites from the 3rd and 4th centuries.However, sources from the 7th and 10th centuries are so scarce that Christianity seems to have diminished during this period.