The Principality of Transylvania (Hungarian: Erdélyi Fejedelemség; Latin: Principatus Transsilvaniae; German: Fürstentum Siebenbürgen; Romanian: Principatul Transilvaniei / Principatul Ardealului; Turkish: Erdel Voyvodalığı / Transilvanya Prensliği) was a semi-independent state ruled primarily by Hungarian princes. Its territory, in addition to the traditional Transylvanian lands, also included the other major component called Partium, which was in some periods comparable in size with Transylvania proper. The establishment of the principality was connected to the Treaty of Speyer. However, Stephen Báthory's status as king of Poland also helped to phase in the name Principality of Transylvania. Although the principality was essentially independent, it existed as an Ottoman vassal state for the majority of the 16th and 17th centuries, overseen by Ottoman Turkish sultans but ruled by Hungarian princes. At various points during this period, the Habsburgs also exerted a degree of suzerainty in the region.
