The written financial instruments upon which the bulk of naval spending depended were called Navy Bills and Victualling Bills. These were issued by the Navy or Victualling Office to merchants upon their delivering goods or services. The bills served as payment but were almost never payable straightaway in cash. A key fact about them is that they were listed and briefly described in a ledger and numbered sequentially. In short, they were registered and dated, and it is crucially important that they were dated and numbered in sequence and that the ledgers were unalterable.