=39. Common wares of commerce in the period of the manor.=—Absolute self-sufficiency was impossible; it was the ideal at which the managers of the manor aimed, but there were few manors which could supply all the necessaries of life. The list, however, of articles which had to be procured by commerce with the outside world was small. Salt was one item, of special importance as it was so difficult to keep live stock through the winter, and the animals had to be killed and salted down. Iron was necessary for various implements, though it was so expensive that it was spared in every possible way. Other articles had to be bought as occasion arose, stones for the mill or tar to keep the murrain from sheep. These wares were essential to existence; by channels so obscure that they cannot now be traced they reached the places where they were wanted, and were purchased with part of the manor’s scanty surplus. Cattle and horses formed also, as is natural, common objects of exchange. =40. The slave trade in Europe.=—One ware which had long been an object of commerce was of especial importance in the period just after the fall of Rome, and, indeed, for some time later; this was slaves. The slave trade extended over all Europe, and had great markets on the Mediterranean, the North, and the Baltic seas. Merchants drove troops of slaves in chains from one country to another, or exported them in lots of 100 or more. In the slave markets of the Baltic as many as 700 are said to have been put up for sale at once. A number of English laws regulated the slave trade of the time. It seems to have been largely confined to convicts, but a law of Alfred provided that a father should not sell his daughter to servitude among strange people. Later the English laws forbade the trade entirely, but we read of Bristol merchants in the eleventh century who not only bought slaves all over England for export to Ireland, but bred them as well; and the trade persisted in various sections even later. =41. Distant commerce confined to rare luxuries.=—Under conditions such as these the term “foreign commerce” in its modern sense is meaningless. The areas which now form the countries of Europe did not specialize in the production of different wares, so that we can trace a regular exchange of products between them. Most of the common wares of commerce circulated inside a restricted area. Only the rich could afford to pay for the transportation of wares over any distance, and they would spend their money only for valuable luxuries. The dignitaries of the church, by reason of their higher culture and connection with a universal organization, created a demand for a few foreign wares, and the governing classes wanted some things which could not be produced at home. Wines and spices were brought up from southern Europe, along the river routes and over the passes of the Alps, and furs were brought down from the North.