This, according to Brants,[1] is essentially a matter upon which more enlightenment will be found in histories of the working classes[2] than in books dealing with the enunciation of abstract theories; nevertheless, it is possible to state generally that it was regarded as the duty of employers to give such a wage as would support the worker in accordance with the requirements of his class. In the great majority of cases the rate of wages was fixed by some public--municipal or corporative--authority, but Langenstein enunciates a rule which seems to approach the statement of a general theory. According to him, when a man has something to sell, and has no indication of the just price from its being fixed by any outside authority, he must endeavour to get such a price as will _reasonably_ recompense him for any outlay he may have incurred, and will enable him to provide for his needs, spiritual and temporal.[3] It was not until the sixteenth century that the fixing of the just price of wages was submitted to scientific discussion;[4] in the fourteenth and fifteenth centuries there is little to be found bearing on this subject except the passage of Langenstein which we have quoted, and some strong exhortations by Antoninus of Florence to masters to pay good wages.[5] The reason for this paucity of authority upon a subject of so much importance is that in practice the machinery provided by the guilds had the effect of preserving a substantially just remuneration to the artisan. When a man is in perfect health he does not bother to read medical books. In the same way, the proper remuneration of labour was so universally recognised as a duty, and so satisfactorily enforced, that it seems to have been taken for granted, and therefore passed over, by the writers of the period. One may agree with Brants in concluding that, 'the principle of just price in sales was applied to wages; fluctuations in wages were not allowed; the just price, as in sales, rested on the approximate equality of the services rendered; and that this equality was estimated by common opinion.'[6] Of course, in the case of slave labour it could not be said that any wage was paid. The master was entitled to the services of the slave, and in return was bound to furnish him with the necessaries of life.[7] [Footnote 1: _Op. cit._, p. 103.] [Footnote 2: An excellent bibliography of books dealing with the history of the working classes in the Middle Ages is to be found in Brants, _op. cit._, p. 105. The need for examining concrete economic phenomena is insisted on in Ryan's _Living Wage_, p. 28.]