Znamyas are special semiographic signs used in manuscripts from the 11th-19th centuries that each correspond to a sequence of sounds of different duration and pitch. Over 500 znamyas existed and are preserved in over 3000 manuscripts found in various Russian libraries. The relationships between znamyas can be modeled using different types of relationships, and the frequency of use of each znamya follows an exponential decay formula related to its rank order of use.