Group size at one hundred creates perceived inner unity and contour

Evidence

One hundred members apparently give the group a certain style, an exactly delimited, rigorous contour in comparison with which a slightly smaller or larger number appears relatively vague and less complete in itself. The Hundred has an inner unity and systematic character which makes it particularly suitable for the formation of genealogical myths. It represents a peculiar synthesis of mystical symmetry and rational sense. — Georg Simmel, The Sociology of Georg Simmel, 4826