The real prerogatives that might formerly be exerted were sometimes of so injurious a nature, that we can hardly separate them from their abuse: a striking instance is that of purveyance, which will at once illustrate the definition above given of a prerogative, the limits within which it was to be exercised, and its tendency to transgress them. This was a right of purchasing whatever was necessary for the king's household, at a fair price, in preference to every competitor, and without the consent of the owner. By the same prerogative, carriages and horses were impressed for the king's journeys, and lodgings provided for his attendants. This was defended on a pretext of necessity, or at least of great convenience to the sovereign, and was both of high antiquity and universal practice throughout Europe. But the royal purveyors had the utmost temptation, and doubtless no small store of precedents, to stretch this power beyond its legal boundary; and not only to fix their own price too low, but to seize what they wanted without any payment at all, or with tallies which were carried in vain to an empty exchequer.[363] This gave rise to a number of petitions from the commons, upon which statutes were often framed; but the evil was almost incurable in its nature, and never ceased till that prerogative was itself abolished. Purveyance, as I have already said, may serve to distinguish the defects from the abuses of our constitution. It was a reproach to the law that men should be compelled to send their goods without their consent; it was a reproach to the administration that they were deprived of them without payment. The right of purchasing men's goods for the use of the king was extended by a sort of analogy to their labour. Thus Edward III. announces to all sheriffs that William of Walsingham had a commission to collect as many painters as might suffice for "our works in St. Stephen's chapel, Westminster, to be at our wages as long as shall be necessary," and to arrest and keep in prison all who should refuse or be refractory; and enjoins them to lend their assistance.[364] Windsor Castle owes its massive magnificence to labourers impressed from every part of the kingdom. There is even a commission from Edward IV. to take as many workmen in gold as were wanting, and employ them at the king's cost upon the trappings of himself and his household.[365] [Sidenote: Abuses of feudal rights.]