Soon after the invention of writing, man attributed to it a symbolic meaning by using its elements in order to define various actualities. Thus, ancient Greeks used the letters of the alphabet as distinctive signs for many objects; judicial and theatrical tablets, law chapters and chapters of books, offerings in temple inventories etc. Quite common was, in addition, the use of painted or incised letters or architectonic members for the correct matching of dressed stones. This tactic is significant to us; on the one hand it throws light on the various construction techniques and on the working scheme of the ancients, proving the logic and care involved in their architecture. On the other hand, this tactic reveals the way letters were used in the numbering systems known to Greeks. Apart from the alphabetic and the decimal, other empirical arrangements of numbers were used.