Ancient Sinhala Numeral Systems Discovered from Palm-leaf Manuscripts in Sri Lanka

Counting is as old as human civilizations and different numbering methods have been indigenous to respective cultures and lands. Until the modern numeric system was introduced, people successfully adopted their own numbering methods, which were used for many millennia. Hence, this study was undertaken as an explorative research project to find out (objective) how ancient monasteries in Sri Lanka indexed and organized the palm-leaf manuscripts in the pre-modern numeric period. In this regard, Sinhala numerals have special linguistic and logical ties with local communities, thus those numbers in the manuscripts are important in indexing and cataloguing the resources. Sri Lanka has historically used (and still uses, to extent) its own numeric system in its ancient palm-leaf manuscripts both in Sinhala and Tamil literary work. This research mainly focused on Sinhala palm-leaf manuscripts preserved in selected Buddhist monasteries in Sri Lanka.
Since this was a qualitative research study carried out for three years, involving observation with the assistance of specialists, there was no predefined population to mention, hence, all the manuscripts available in the study areas were taken into consideration. Manual textual analysis of 4,568 manuscripts unveiled five different types of Sinhala numerals corresponding to different timelines, and disclosed the evolution of number system through various reigns. The numeral systems discovered through this study are Sinhala illakkam, Lith illakkam, Pansal Hodiya, Indo-Arabic numbers, and Tamil numbers. The Sinhala illakkam was the oldest numeral system found in palm leaf writings during 1754-1825 AD. It was specifically used for Pali and literary contents. The Lith illakkam was as old as Sinhala illakkam and was used for astrological and native medicinal content in palm-leaf manuscripts. The most prominent numeral system was Pansal Hodiya, which was later replaced by the Indo-Arabic numeral system, which took place gradually since 16^th Century (Senevirathne, 2018). The Tamil numeral system was also identified. Digitalization process of palm-leaf manuscripts will be the next level of this study, which is crucial for information access and preservation of the palm-leaf manuscripts. Additionally, incorporating AI tools to analyze digitized materials could create new opportunities for future research in this domain, such as automated text detection and content analysis.