Given the question: Burgruine Ortenburg - Burgruine Ortenburg is a mediaeval castle near Baldramsdorf in Carinthia Austria.It was erected in the late 11th century by ministeriales of the Bavarian Prince-Bishops of Freising who then held large possessions in the Duchy of Carinthia. Their descendants began to call themselves Counts of Ortenburg. Given a choice of categories company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, the text refers to which one?
The answer is:
Building