Bled was the site of a Hallstatt settlement in the early Iron Age, but as it was far from the main trade routes, the Romans gave it short shrift. More importantly, from the 7th century the early Slavs came in waves, establishing themselves at Pristava below the castle, on the tiny island and at a dozen other sites around the lake.
Around the turn of the first millennium, the German Emperor Henry II presented Bled Castle and its lands to the Bishops of Brixen in South Tyrol, who retained secular control of the area until the early 19th century when the Habsburgs took it over.
Bled’s beauty and its warm waters were well known to medieval pilgrims who came to pray at the island church; the place made it into print in 1689 when Janez Vajkard Valvasor described the lake’s thermal springs in The Glory of the Duchy of Carniola. But Bled’s wealth was not fully appreciated at that time, and in the late 18th century the keeper of the castle seriously considered draining Lake Bled and using the clay to make bricks.
Fortunately, along came a Swiss doctor named Arnold Rikli, who saw the lake’s full potential. In 1855 he opened baths where the casino now stands, taking advantage of the springs, the clean air and the mountain light. With the opening of the railway from Ljubljana to Tarvisio (Trbiž) in 1870, more and more guests came to Bled and the resort was a favourite of wealthy Europeans from the turn of the century right up to WWII. In fact, under the Kingdom of Serbs, Croats and Slovenes, Bled was the summer residence of the Karadžordževići, the Yugoslav royal family.