Scribal abbreviations or sigla (singular: siglum) are abbreviations used by ancient and medieval scribes writing in various languages, including Latin, Greek, Old English and Old Norse. In modern manuscript editing (substantive and mechanical) sigla are the symbols used to indicate the source manuscript (e.g. variations in text between different such manuscripts) and to identify the copyists of a work. History Abbreviated writing, using sigla, arose partly from the limitations of the workable nature of the materials (stone, metal, parchment, etc.) employed in record-making and partly from their availability. Thus, lapidaries, engravers, and copyists made the most of the available writing space. Scribal abbreviations were infrequent when writing materials were plentiful, but by the 3rd and 4th centuries AD, writing materials were scarce and costly. During the Roman Republic, several abbreviations, known as sigla (plural of siglum 'symbol or abbreviation'), were in common use in inscriptions, and they increased in number during the Roman Empire. Additionally, in this period shorthand entered general usage. The earliest known Western shorthand system was that employed by the Greek historian Xenophon in the memoir of Socrates, and it was called . In the late Roman Republic, the Tironian notes were developed possibly by Marcus Tullius Tiro, Cicero's amanuensis, in 63 BC to record information with fewer symbols; Tironian notes include a shorthand/syllabic alphabet notation different from the Latin minuscule hand and square and rustic capital letters. The notation was akin to modern stenographic writing systems. It used symbols for whole words or word roots and grammatical modifier marks, and it could be used to write either whole passages in shorthand or only certain words. In medieval times, the symbols to represent words were widely used; and the initial symbols, as few as 140 according to some sources, were increased to 14,000 by the Carolingians, who used them in conjunction with other abbreviations. However, the alphabet notation had a "murky existence" (C. Burnett), as it was often associated with witchcraft and magic, and it was eventually forgotten. Interest in it was rekindled by the Archbishop of Canterbury Thomas Becket in the 12th century and later in the 15th century, when it was rediscovered by Johannes Trithemius, abbot of the Benedictine abbey of Sponheim, in a psalm written entirely in Tironian shorthand and a Ciceronian lexicon, which was discovered in a Benedictine monastery (). To learn the Tironian note system, scribes required formal schooling in some 4,000