As long as the natural freedom of man continued unrestrained by a multiplicity of laws, every person was at liberty to build on his own lands and possessions whatever he thought proper, and not only water- but also wind-mills. This freedom was not abridged even by the Roman law[452]. But as it is the duty of rulers to consult what is best for the whole society under their protection, princes took care that no one should make such use of common streams as might impede or destroy their public utility[453]. On this account no individual was permitted to construct a bridge over any stream; and it is highly probable that the proprietors of land, when water-mills began to be numerous, restrained, from the same principle, the liberty of erecting them, and allowed them only, when after a proper investigation they were declared to be not detrimental. Water-mills, therefore, were included among what were called _regalia_; and among these they are expressly reckoned by the emperor Frederic I.[454] On small streams however which were not navigable, the proprietors of the banks might build mills everywhere along them[455]. The avarice of landholders, favoured by the meanness and injustice of governments, and by the weakness of the people, extended this regality not only over all streams, but also over the air and wind-mills. The oldest example of this with which I am at present acquainted, is related by Jargow[456]. In the end of the fourteenth century, the monks of the celebrated but long since destroyed monastery of Augustines, at Windsheim, in the province of Overyssel, were desirous of erecting a wind-mill not far from Zwoll; but a neighbouring lord endeavoured to prevent them, declaring that the wind in that district belonged to him. The monks, unwilling to give up their point, had recourse to the bishop of Utrecht, under whose jurisdiction the province had continued since the tenth century. The bishop, highly incensed against the pretender who wished to usurp his authority, affirmed that no one had power over the wind within his diocese but himself and the church at Utrecht, and he immediately granted full power, by letters patent, dated 1391, to the convent at Windsheim, to build for themselves and their successors a good wind-mill, in any place which they might find convenient[457]. In the like manner the city of Haerlem obtained leave from Albert count palatine of the Rhine to build a wind-mill in the year 1394[458].