Throughout the Ottoman Empire, land was always the major source of revenue and surplus and thus inevitably a major source of contention. Myriad property-rights disputes were recorded in the registers of the local kadı courts and archives of the various ministries in Istanbul. Conflicts over the agricultural surplus revealed in such documentation demonstrate, for instance, that peasants in the sixteenth century not only contested taxes imposed on them but also opposed the illegal transfer of land titles by the sipahis (İnalcık 1997, p. 72). By the middle of the sixteenth century, the practice of selling state-owned miri lands–which by legal definition could not be bought or sold–had become widespread, sometimes even confirmed by the rulings of the local kadı courts. The stamp of şeriyye implicit in the kadı's ruling meant in effect that the land subject to sale was taken out of the miri land regime and placed in the legal category of freehold mülk lands (İnalcık 1997, p. 112).