Transylvania has many links to what is now, Hungary and Romania. We will begin with Dracula... rather with Prince Vlad Tepes of Wallachia, who was born int eh border so Transylvania. Wallachia and Moldova would int eh late 1800s merge to become what would become Romania. The Prince of Romania? Prince Carol I. He would later become King Carol I of Romania.
Micheal the Brave into Alba Iluia, in 1599. This was the one year when between 1599-1600 where what would become Greater Romania, in 1919, would be unified. After this time, Transylvania was a part of the Kingdom of Hungary.