In "great" commerce the guild regulated the conditions which made a bargain valid, the duty of paying the _denier à Dieu_, and the earnest-money, the regular term for completing payment, the rate of discount, and the transparent methods of avoiding the ban placed on interest by the Church,[46] the methods of book-keeping, etc. By means of these Statutes commerce was eventually to emerge armed with full rights; and as the failure of one member to fulfil his undertakings might compromise all the others, we can understand, even if we cannot approve, the severity of the penalties inflicted on a bankrupt, the posting up of his name and effigy, his expulsion from the guild, his imprisonment and occasionally his banishment from the city. One serious result of this constant and perfectly legitimate effort to assure the success of the guild was that it produced a strong desire to reduce, or if possible do away with, competition. The Middle Ages did not understand rights except under the form of privileges, and the guild always tended to arrogate to itself the monopoly of the craft which it carried on in a city. It even tried to exclude neighbouring towns from the market, and this was the secret of the desperate struggles which set at enmity Bruges and Ghent, Siena, Pisa, and Florence, Genoa and Venice, etc. There is ample proof of this exclusive spirit. At first the guilds tried to keep their processes secret, just as to-day a nation makes a mystery of its new submarine or explosive. Woe to him who betrayed the secret which gave the guild its superiority over the others! He was punished by his fellows and by the law. The merchants of the Calimala swore not to reveal what was said in the Councils of the guild. Florence owed part of her wealth to the fact that for long she alone knew the secret of making gold and silver brocade. A tragic example of what it might cost to be indiscreet may be found in a Venetian law of 1454: "If a workman carry into another country any art or craft to the detriment of the Republic, he will be ordered to return; if he disobeys, his nearest relatives will be imprisoned, in order that the solidarity of the family may persuade him to return; if he persists in his disobedience, secret measures will be taken to have him killed wherever he may be." The following is an example of the jealous care with which the guild tried to prevent any encroachment on its domain: in Paris the guild of the bird fanciers attempted, though unsuccessfully, to prevent citizens from setting on eggs canaries which they had caged, as it injured the trade of the guild.[47]