By a Mandate of 1538, formulated by Thomas Cromwell, every parish was required to purchase a 'sure coffer' to which there were two keys, one held by the parson and the other by a churchwarden. Then minister was then required to enter into a book details of every marriage, christening and burial at which he officiated. The entries were to be made on Sunday after the service and witnessed by the churchwarden. The book was then to be deposited in the newly acquired parish chest. There are approximately 1500 parishes in which the register entries begin as early as 1538. In practice the entries were usually made on pieces of paper and were not written up in book form until 1598. The amount of detail recorded concerning an event was dependent upon the whim of the person making the entry and can vary from the basic name and date to full details of interested parties. From 1812 special books were issued which contained printed forms for the details to be entered on.