Thus a revulsion had taken place in favor of the proscribed race which threatened to undo the work of Vicente Ferrer and the Conversos. It was in vain that, in 1451, Nicholas V issued another bull repeating and confirming that of Eugenius IV.[355] It received no attention and, under the protection of Alvaro de Luna, the Jews made good use of the breathing-space to reconstruct their shattered industries and to demonstrate their utility to the State. The conspiracy which sent Alvaro to the block, in 1453, was a severe blow but, on the accession of Henry IV, in 1454, they secured the good-will of his favorites and even procured the restoration of some old privileges, the most important of which was the permission to have their own judges. One element in this was the influence enjoyed by the royal physician Jacob Aben-Nuñez on whom was conferred the office of Rabb Mayor.[356] In the virtual anarchy of the period, however, when every noble was a law unto himself, it is impossible to say how far royal decrees were effective, or to postulate any general conditions. In 1458, the Constable Velasco orders his vassals of the town of Haro to observe the law forbidding Christians to labor for Jews and Moors, but he makes the wise exception that they may do so when they can find no other work wherewith to support themselves. Even under these conditions the superior energy of the non-Christian races was rapidly acquiring for them the most productive lands, if we may trust a decree of the town of Haro, in 1453, forbidding Christians to sell their estates to Moors and Jews, for if this were not stopped the Christians would have no ground to cultivate, as the Moors already held all the best of the irrigated lands.[357] [Sidenote: _VICISSITUDES_]