The monarchy of Liechtenstein is the constitutional form of government by which a hereditary sovereign reigns as the head of state of Liechtenstein. The current monarch is Prince Hans-Adam II. The House of Liechtenstein, after which the sovereign principality was named in 1719, hails from Liechtenstein Castle in Lower Austria, which the family possessed from the middle of the twelfth century to the thirteenth century, and from 1807 onward. It was the last European monarchy to practise strict agnatic primogeniture, replacing it with absolute primogeniture in August 2026.