Incorporated banks are usually started by private initiative but owe their actual legal existence and status to a special law, to the requirements of which they must conform before they are permitted to do business. Their right to do business is usually evidenced by a document known as a charter, executed and delivered by a public officer legally endowed with the requisite authority, or passed in the form of a law by the legislative organs of the state. Charters of the latter kind are known as special charters and are rarely used nowadays, except in the case of institutions of a peculiar character, endowed with special functions. The central banks of Europe owe their existence to such charters, as did also the first and second United States banks. In the early history of the United States special charters were uniformly employed by the states, but for many years general incorporation laws have been the rule, on compliance with the requirements of which persons who desire to incorporate banks can secure charters. In federal states, both the federal government and the governments of the constituent states frequently have and exercise the right to incorporate banks. In the United States, banks incorporated by the federal government under the terms of a general law, originally passed in 1863 and many times amended since that date, are known as _national_ banks, and those incorporated by the states under the terms of general banking acts or of general incorporation laws are known as _state_ banks. These latter are endowed with privileges which enable them to exercise commercial and some investment banking functions. Other banks also are incorporated by our states under the terms of general laws, which are known as savings banks and trust companies. The former, as the name implies, are institutions primarily designed for the encouragement, collection, and investment of savings. The latter are called trust companies because the earliest institutions of this type made the execution of trusts of various kinds their exclusive business. Banking functions were later added and in many cases have now assumed chief importance.