The study of the history of script.
From the Greek palaiographia, meaning 'ancient writing', paleography is the study of the history of scripts, their adjuncts (such as abbreviation and punctuation), and their decipherment. The fifteenth-century humanists (see Humanist minuscule) were the first to attempt to distinguish styles of handwriting according to date, but the discipline really began to develop during the second half of the seventeenth century. At this time, Jean Bolland, leader of a group of Flemish Jesuits, was charged by the Holy See with producing an authoritative compendium of saints' lives. In the process, the Bollandists established criteria for determining the authenticity of documents through the analysis of script. Jean Mabillon, a Benedictine monk of St. Germain des Près, then published De re diplomatica (1681), which includes a section on the history of handwriting and uses paleographic means to argue for the validity of certain ancient grants to the Benedictine Order. Mabillon's principles for assessing the authenticity of documents gave rise to the formal discipline of paleography (or diplomatic, as it was known until the nineteenth century). Subsequent landmarks in the discipline include the Nouveau traité de diplomatique (1750-65) by the Benedictines René-Prosper Tassin and Charles-François Toustain, Charles-François-Bernard de Montfaucon's Palaeographia graeca (1708), and the work of Francesco Scipione Maffei of Verona (1675-1755). The twentieth century has witnessed the development of several major schools of paleography, defined by the approaches of key scholars, such as Ludwig Traube and E. A. Lowe.
Michelle Brown, Understanding Illuminated Manuscripts (Malibu, CA: J. Paul Getty Museum in association with the British Library, c1994).