Spelman, Sandford, Madox, and other English writers their contemporaries, and the Treatises of Mabillon, Heineccius, and the Benedictine authors of the Nouveau Traité de Diplomatique, show the value and importance that have been attached to them by competent judges in the earlier stages of archaeological science.
In a critical acquaintance with this interesting subject has been found one of the most efficient means of determining the genuineness of charters and the like, of identifying the persons by whom they were granted with their respective families, of appropriating the documents to the proper individuals when there were several of the same name, and of ascertaining the dates of undated instruments. In many cases they have added materially to the information contained in the writings to which they were appended; as by supplying or explaining a name, or mentioning an office which an individual held, or showing some particular relation in which he stood to others. For, since the execution of the seal was rarely contemporaneous with the sealing of the instrument, they are virtually two independent documents brought together, relating to the same person, and serving to explain and elucidate each other.
Apart, however, from written documents, and as detached impressions, seals, or the matrices themselves, are also fruitful sources of information. They not only supply what is deficient in impressions elsewhere found attached, but contribute to our knowledge in various ways that might not at first be anticipated. Official seals, and seals of ecclesiastics, bring to light sometimes the names of those who have filled offices, and enjoyed dignities, and been forgotten; and sometimes revive the knowledge of the existence of offices which had themselves fallen into oblivion. In like manner common seals occasionally attest the existence of communities of which all remembrance had ceased; while personal seals restore to family trees grafts and scions which had dropped away, and would otherwise have remained wholly unknown. On heraldry, which has proved so serviceable in the investigation of medieval antiquities, they afford most valuable information; since from them we learn the earliest examples of the art, with few exceptions, and much of the subsequent usages and practice of it until the modern system prevailed. Analogous to brasses and other sepul-
