In 1634, the castle and the estate passed into the hands of the Italian nobleman Ottavio Piccolomini de Arragona as a reward for his help in removing Wallenstein. The then thirty-five-year-old Ottavio had already completed a long military service, during which he had gained a wealth of war experience. He joined the army at the age of seventeen, took part in the Battle of White Mountain, later became commander of Wallenstein's bodyguard, and at the Battle of Lützen Ottavio's “Black Riders” killed King Gustav II of Sweden. Hand in hand with his military successes went his social rise, and Ottavio was first promoted to the rank of count for his services, was rewarded by King Philip IV of Spain with the Duchy of Amalfi for his defeat of the French army at Thionville in 1639, and received the Order of the Golden Fleece in 1643. Towards the end of the war he was at the head of the imperial troops in Bohemia. Finally, after the diplomatic negotiations on the terms of the Peace of Westphalia, in which he participated as an imperial plenipotentiary, he crowned his successful career with the hereditary title of Prince of the Empire. He was also a recipient of the Order of St. Stephen of Pisa. The Piccolomini family owned the estate until 1783 and during his reign the castle was given its present form.