Lake Bled is a lake in the Julian Alps of the Upper Carniolan region of northwestern Slovenia, where it adjoins the town of Bled. The lake surrounds Bled Island. The island has several buildings, the main one being the pilgrimage church dedicated to the Assumption of Mary, built in its current form near the end of the 17th century, and decorated with Gothic frescos from around 1470 in the presbyterium. Bled Castle is a medieval castle built on a precipice above the city of Bled in Slovenia, overlooking Lake Bled. According to written sources, it is the oldest Slovenian castle, first being mentioned in 1011.