symbols; this later increased to some 5,000 symbols and then to some 13,000 in the medieval period (4th to 15th centuries AD); the meanings of some characters remain uncertain. Sigla were mostly used in lapidary inscriptions; in some places and historical periods (such as medieval Spain) scribal abbreviations were overused to the extent that some are indecipherable. Forms The abbreviations were not constant but changed from region to region. Scribal abbreviations increased in usage and reached their height in the Carolingian Renaissance (8th to 10th centuries). The most common abbreviations, called , were used across most of Europe, but others appeared in certain regions. In legal documents, legal abbreviations, called , appear but also capricious abbreviations, which scribes manufactured ad hoc to avoid repeating names and places in a given document. Scribal abbreviations can be found in epigraphy, sacred and legal manuscripts, written in Latin or in a vernacular tongue (but less frequently and with fewer abbreviations), either calligraphically or not. In epigraphy, common abbreviations were comprehended in two observed classes: The abbreviation of a word to its initial letter; The abbreviation of a word to its first consecutive letters or to several letters, from throughout the word. Both forms of abbreviation are called suspensions (as the scribe suspends the writing of the word). A separate form of abbreviation is by contraction and was mostly a Christian usage for sacred words, or ; non-Christian sigla usage usually limited the number of letters the abbreviation comprised and omitted no intermediate letter. One practice was rendering an overused, formulaic phrase only as a siglum: DM for ('Dedicated to the Manes'); IHS from the first three letters of ; and RIP for ('rest in peace')) because the long-form written usage of the abbreviated phrase, by itself, was rare. According to Traube, these abbreviations are not really meant to lighten the burden of the scribe but rather to shroud in reverent obscurity the holiest words of the Christian religion. Another practice was repeating the abbreviation's final consonant a given number of times to indicate a group of as many persons: denoted , thus, denoted ; however, lapidaries took typographic liberties with that rule, and instead of using to denote , they invented the form. Still, when occasion required referring to three or four persons, the complex doubling of the final consonant yielded to the simple plural siglum. To that effect, a vinculum (overbar) above