Which King of Romania Was the First To Have Transylvania as a Part of His Kingdom?

Transylvania has been a part of the cultural identity of two countries for centuries.  Both Hungary and Romania identify with Transylvania, and in the last century, Transylvania was, at different times, a part of both countries.  At the end of the 1800s, there were many new Eastern European countries created.  Most, if not all had been a part of the Ottoman Empire, and one of them was the country of Romania.  At first this was not a Kingdom, but rather a Princedom, and the first to men to hold the throne of Romania, were named at such.  Before this time Transylvania was a part of the Kingdom of Hungary.

When Transylvania became a part of the Kingdom of Romania in 1919, who was the king at the time?  The Kings' name was King Ferdinand, and his wife was to become the more famous of the two.

Here is a bit of trivia: This monarch was not as beloved by the population as his wife, and he was not Romanian by birth — his eldest son was, however, born in Romania in 1893.  

The Romanian royal house was of Germanic origin.  The first king was King Carol I, and he reigned until 1914.  He and his wife Queen Elizabeth only had one child a daughter, who did not survive childhood, and because the throne of Romania needed an heir, Carol made one of his nephews Crown Prince of Romania.   In 1922, his nephew Ferdinand was crowned in Transylvania, in the city of Alba Iulia.

King Ferdinand, the second King of Romania, and his wife, Queen Marie, became the first of the three kings to claim Transylvania as a part of Romania.  One of the many castles and cities that became a part of Romania was Bran Castle.  The castle and Transylvania have been a part of the country of Romania since 1919.

Queen Marie of Romania