Economically the monasteries were really productive centers. Their artisans at first supplied only the needs of the monastic community itself; then, as there was a surplus, the abbots established industrial centers for wider distribution outside the monastic precincts. The oldest of such Carolingian factories, so far as we know, was St. Riquier, which contained special quarters for each trade. Indeed, many continental cities owe their origin to this industrial movement. The workingmen were organized in unions, guilds, or confraternities, whose purpose was primarily charity, resembling mutual aid societies, with features providing for insurance in case of loss by fire or shipwreck.
As villa manufacture was confined to articles of common need, more elaborate tastes had to be gratified by importation from places beyond the limits of the northern countries of Europe. The Emperor gave great attention to guarding the frontiers, so that foreign commerce could be carried on in security. The great trade routes followed the rivers. There was a regularly developed system of markets and fairs held near the cities and the monasteries, as in the case of St. Denis, near Paris, where for a space of four weeks goods were exposed for sale by traders from Spain, Southern France, and Lombardy.
In Germany and in the more remote portions of the Empire, near the Slavic frontiers, the government established shelters and exchange offices for the convenience of merchants, and strict care was taken that arms were not sold to the enemy. Chief among the entrepots of commerce was the city of Mainz, famous for its cloth manufacture. Charles planned to make of it the great imperial economic center, and in pursuance of this program provided for the construction of a wooden bridge over the Rhine. He proposed also to build a canal to connect the Danube with the Rhine. But the bridge was destroyed by fire, and the canal offered too serious difficulties for the engineers of his age to surmount.
Trade between the Empire and Great Britain and Ireland was encouraged. There was a lighthouse at Boulogne, and at Quentovia, now Étaples, a customs-house was established and placed under the supervision of Gerrold, a shrewd man of affairs, abbot of St. Wandrile. The constant stream of pilgrims passing from the islands was protected by the Emperor, and they proved useful in drawing closer the commercial ties with these remoter portions of the civilized world. Naturally the Mediterranean commerce was the more important, and the Emperor was careful to keep up good relations with Eastern princes, both Christian and Moslem.
Imports consisted of purple stuffs, silk cloaks of various colors, worked leather, perfumes, unguents, and medicinal plants, spices, Indian pearls, Egyptian papyrus, and even exotic animals, such as monkeys and elephants. The cities in Southern France were especially frequented for trade, many of them having a cosmopolitan population. The Jews were valued for their business capacity, and also for their knowledge of languages and medical science. They were not allowed to own landed property, but no restrictions were placed on their loan operations, or on their commercial ventures.
A marked improvement is noted in the coinage. After 800 the bust of the Emperor appears with an indication of the Roman military cloak and the words “Carolus Imperator”; on the reverse is a temple with a cross and the inscription “Religio Christiana.”
The financial administration of the government offered few complications, because the obligations on the state in the way of expenses were most limited. The chief item in the imperial budget, which preserved the personal and household character of the Merovingian period, was for the maintenance of the royal palaces, for the presents made by the king to churches, to foreign princes, or to the great officers of the Empire. Direct taxes were of the capitation type, graded according to the position of the individual taxed. The ordinary fiscal resources were made up from the income of the King from his own estates, from tributes paid by vassal nations, from war booty, obligatory annual gifts, and indirect taxes. The revenue from the royal estates, which were excellently managed, was considerable, and there must have been a large sum credited to the account of booty from the various successful wars.
The “benevolences,” to use a term familiar in the constitutional and financial history of England, were not fixed, and the records speak in an indefinite way of the contribution offered by faithful subjects of the Empire in the annual assemblies. But it is plain that these so-called gifts included precious stones and valuable fabrics, as well as gold and silver.
The principal indirect taxes were in the form of personal service, rather than in money payments. Local taxation meant special work on roads, bridges, and making dikes. For the great bridge at Mainz, labor was called for from many localities, because it was an imperial work, intended for the common benefit of the whole Empire. Transportation dues are frequently mentioned in the Carolingian laws, as well as the right of “lodging,” by which the inhabitants of a community were obliged to lodge and entertain the King and his officials on their travels, and to receive the representatives of foreign powers and others, to whom the royal privilege was given. A bishop, for example, had the right to receive forty loaves a day, three lambs, three measures of ale, a gallon of milk, three chickens, fifteen eggs, and four measures of feed for his horses.
The greatest difficulties of the government were not financial, but military, for the state of warfare was almost continuous, especially along the Alps, the Pyrenees, and from the Eider to the lower Danube. The summons for calling together the units of the military forces was either carried by means of direct envoys or by letters sent to the counts, bishops, and abbots, and sometimes by the “missi.” These officials had to see that all those who were liable to service should be prepared to take their places when the call to arms was given. One of the “missi” writes: “let all be so prepared that, if the order to leave comes in the evening, they will leave without delay for Italy on the morning of the next day, but if it comes in the morning, in the evening of the same day.”