Transylvania is a part of the country of Romania, and has been since 1919. Before that time it it was a part of the Kingdom of Hungary (which was itself a part of the Empire of Austria.) Before the late 1800s there was no country by the name of Romania, but it became a princedom in the early 1870s. At this time, the was a unification of the two principalities, Wallachia and Moldavia. Transylvania was not a part of this formal union.
Even then, Transylvania, and other areas were of interest to the Romanian government of the time. When Romania became a kingdom under King Carol I, it was simply another small Eastern European country, along with Greece, Bulgaria and others. There was tension between these nations, as there was across Europe.
Something was about to happen.
In 1914, in the small Kingdom of Serbia an archduke of Austria and his wife, a countess, were assassinated and this lead to the beginning of World War I. Romania would later make the choice to fight alongside the Allies, and many believe this was because of Queen Marie's
influence on her husband, King Ferdinand.
At the conclusion of the War, Transylvania became a large part of Romania. The Kingdom of Romania remained this way until 1940, when there was another treaty signed by which the Northern half of Transylvania was returned (or given, depending on your perspective) to Hungary. Transylvania, Romania and its people are at the heart of this story.
It was a queen who made the suggestion that Romania should fight with the Allies, and she also went to the Paris Peace Conference and positioned Transylvania and Besserabia in the process which would increase her Kingdom. Most of this territory had many ethnic Romanians living there.
The fact remains that there was a large population of Romanians who lived in Transylvania, and they identify with Romania, but there were also populations of Germans who identified with Transylvania (then Romania), and ethnic Hungarians. All this means is that Transylvania has a diverse culture; one which the Romanian people play a strong part in. As for Vlad Tepes, there was a link to the Romanian Royal family with an English Princess.
She became Queen of Romania, where he once ruled as Prince of Wallachia.