In the 15th century disturbances in the boroughs led to the creation of new constitutions, some of which were the outcome of royal charters, others the result of parliamentary legislation. The development of the law of corporations also at this time compelled the boroughs to seek new charters which should satisfy the now exacting demands of the law. The charters of incorporation were issued at a time when the king's government was looking more and more to the borough authorities as part of its executive and judicial staff, and thus the government was closely interested in the manner of their selection. The new charters were drafted in such a way as to narrow the popular control. The boroughs were placed under the control of a corporation headed by a mayor, and in most cases leading to no concept of popular control, the whole system of appointment to the corporation being one of co-option by existing members. Absence of popular protest to this may in part be due to old popular control being more nominal than real, and the new charters gave as a rule two councils of considerable size. These councils bore a heavy burden of taxation in meeting royal loans and benevolences, paying per capita, like the magnates of the 12th century, and for a time there is on the whole little evidence of friction between the governors and the governed. Throughout, unpopular changes or neglect in the closest of corporations had a means of official protest, though no means of execution, in the presentments of the leet juries and sessions juries. By means of their "verdicts" they could use threats against the governing body, express their resentment against acts of the council which benefited the governing body rather than the town, and call in the aid of the justices of the assizes (judges, in the seasons of sittings outside of London, "assizes") where the members of the governing body were suspected of fraud.