The most important series of official correspondence is the Papal Letters, calendared from 1198 to 1404 in 4 vols.
Many of his letters, articles, injunctions &c., are calendared in the published volumes of the "State Paper" series of the reign of Elizabeth.
Archives have been reformed, their contents catalogued or calendared; government commissions have rescued numberless documents from oblivion or destruction, and learned societies have supplemented and criticized this work and co-ordinated the results.
The Scottish and Irish state papers are calendared in separate series and without much system.
Its value, however, varies; the earlier volumes are not so full as the later, the documents are not so well calendared, and some classes are excluded from earlier, which appear in the later, volumes.