From the World heritage inscription:
The Castle of Wartburg is an outstanding monument of the feudal period in central Europe. It is rich in cultural associations, most notably its role as the place of exile of Martin Luther, who composed his German translation of the New Testament there. It is also a powerful symbol of German integration and unity.
The legendary creation of the castle is attributed to Count Ludwig der Springer. The first steps in its construction were taken in 1067, and it became one of the key points in the early years of Ludovician sovereignty. This sovereignty grew more firmly established during the first half of the 12th century. Raised to the dignity of Landgraves, the Ludovicians supported the policies of the Stauffen emperors. The building of the palace in the second half of the 12th century illustrates their status as Princes of the Empire. In 1227 Heinrich Raspe IV, the brother of Ludwig IV, succeeded him and, espousing the pope’s cause, was appointed King of Germany on the initiative of Innocent IV. His death in 1247 ended the Ludovician dynasty.
Wartburg Castle seems to be a crossroad for much of German history. It was important in medieval German history as a fortification of the Ludovicians, it was where Martin Luther hid and translated the Bible into German, it was important in the 19th Century unification of Germany, and Wagner used it as the backdrop for his opera: Tannhäuser.
If you arrive in Eisenach by train, you will probably need to take a taxi to get to Wartburg Castle. It is less than a 10 minute trip, but it is located on the top of a small mountain and is a fair walk from the train station.
This was the fifth stop on my November 2011 Eurail trip of European UNESCO World Heritage Sites.
View my complete list of UNESCO World Heritage sites.