St. George's Basilica is the oldest church building within the Prague Castle complex. It is also the best-preserved Romanesque church in Prague. Within the church lie several tombs of major historic importance. In the Gothic Chapel of St. Ludmila lies the tomb of St. Ludmila, the saint and widow of the 9th century ruler Prince Borivoj. Also buried in the basilica are Prince Vratislav and Boleslav II.