The men of business may be divided into two classes, according as they undertook work for the State or on their own account entirely. It does not follow that these two classes were mutually exclusive; a man might very well invest his money in both kinds of undertaking, but these two kinds were totally distinct, and called by different names. A public undertaking was called _publicum_,[109] and the men who undertook it _publicani_; a private undertaking was _negotium_, and all private business men were known as _negotiatores_. The publicani were always organised in joint-stock companies (_societates publicanorum_); the negotiatores might be in private partnership with one or more partners,[110] but as a rule seem to have been single individuals. We will deal first with the publicani. In a passage of Livy quoted just now it is stated that at the beginning of the Hannibalic war money was advanced to the State by societates publicanorum; Livy also happens to mention that three of these competed for the privilege. Thus it is clear that the system of getting public work done by contract was in full operation before that date, together with the practice on the part of the contractors of uniting in partnerships to lessen the risk. System and practice are equally natural, and it needs but a little historical imagination to realise their development. As the Roman State became involved in wars leading to the conquest of Italy, and in due time to the acquisition of dominions beyond sea, armies and fleets had to be equipped and provisioned, roads had to be made, public rents to be got in, new buildings to be erected for public convenience or worship, corn had to be procured for the growing population, and, above all, taxes had to be collected both in Italy and in the provinces as these were severally acquired.[111] The government had no apparatus for carrying out these undertakings itself; it had not, as we have, separate departments or bureaux with a permanent staff of officials attached to each, and even if it had been so provided, it would still have found it most convenient, as modern governments also do, to get the necessary work carried out in most cases by private contractors. Every five years the censors let the various works by auction to contracting companies, who engaged to carry them out for fixed sums, and make what profit they could out of the business (_censoria locatio_). This saved an immense amount of trouble to the senate and magistrates, who were usually busily engaged in other matters; nor was there at first any harm in the system, so long as the Romans were morally sound, and incapable of jobbing or scamping their work. The very fact that they united into companies for the purpose of undertaking these contracts shows that they were aware of the risk involved, and wished as far as possible to neutralise it; it did not mean greed for money, but rather anxiety not to lose the capital invested.