In the year 1359, he founded the Eastern Orthodox Metropolis of Ungro-Wallachia[contradictory].

After initially resisting pressures to become the Kingdom of Hungary's vassal, he yielded to King Louis I in 1354, and recognized the right of the Roman Catholic Church to establish missions in his principality, as well as the privilege of Saxon traders from Brașov to transit Wallachia without paying duties.

In 1355, Nicolae Alexandru and the King of Hungary reached an agreement in return for Severin.

His epitaph reads: Firstly, he married Lady Maria, of the magyar Lackfi family located in Transylvania.The couple had two children: Through Elizabeth's youngest daughter, Katarina of Oppole, Nicolas Alexander become ancestor for all European royal families including Romanian royal family.

[1] The marriage produced three children: The mother of Vladislav I of Wallachia may be Clara Dobokai.