The Commonwealth and State governments exercise the royal prerogative all the time. They enter treaties, deal with wastelands and pardon offenders. Usually the prerogative fits with modern constitutional arrangements and is not given a second thought. However, the curious example of the prerogative to swans does give pause for thought. The medieval origins of the prerogative highlight the authoritarian foundation of all prerogatives; it arose as an arbitrary confiscation of valuable property when the King was a despot. That the Queen still asserts a prerogative to swans today, long since swans ceased to be valuable as a commodity, shows that the prerogative can persist on its own steam, even though the original reasons for the prerogative have fallen away. Yet a prerogative to black swans has never been asserted, revealing there is a limit to the prerogative's inertia. In the end, the prerogative remains a means to exert power.