The aim of this treatise is to define the Roman and the Roman-typed theatre cavea plans, clearify the process of the formation and spread of those plans and draw out some features of ancient Mediterranean Architecture through the Roman theatre cavea plans. It consists of three papers and in this first paper are discussed the principal characters of the Roman theatre cavea plans, the three elements of creating the plans, three types of cavea plan (A, B, C type) of the Roman-typed theatre and the formation of the predecessor of the A type until the early first century B.C.
