Prague Castle was most likely founded in around 880 by Prince Bořivoj of the Premyslid Dynasty (Přemyslovci). According to the Guinness Book of World Records, Prague Castle is the largest coherent castle complex in the world, with an area of almost 70,000 m². A UNESCO World Heritage site, it consists of a large-scale composition of palaces and ecclesiastical buildings of various architectural styles, from the remains of Romanesque-style buildings from the 10th century through Gothic modifications of the 14th century. The famous Slovenian architect Josip Plečnik was responsible for extensive renovations in the time of the First Republic (1918-1938). Since the Velvet Revolution, Prague Castle has undergone significant and ongoing repairs and reconstructions.