A Prince of Transylvania?

Yes there is such a thing as a Prince of Transylvania. But the question I'm asking is where is this prince now? And Why this picture?

Some of the former princes of Transylvania include: Micheal the Brave, Prince of Transylvania, Prince of Wallachia and Prince of Moldovia.

Another, The Blessed Karl of Austria, Grand Prince of Transylvania, King of Hungary.

He died in 1922, and his son commonly known as Otto von Hapsburg is pretender to this throne. The picture above is of Otto and his great-uncle, Emperor Franz Joesph of Austria.

My Question For you Today is this: Can you name other Princes or Grand Princes of Transylvania?