In 1649 Christian’s son and successor King Frederik III of Denmark had the seat of the Holstein administration moved to Glückstadt, whereafter the duchy became known as Holstein-Glückstadt. In 1773 the town became the capital of all Holstein lands, when the lands of the Holstein-Gottorp line were finally incorporated. During the War of the Sixth Coalition in 1814 Glückstadt was blockaded by the allies and capitulated, whereupon its fortifications were demolished. In 1830 it was made a free port.