Professor Kleiner traces the evolution of Roman architecture from its beginnings in the eight-century B.C. Iron Age through the late Republican period. The lecture features traditional Roman temple architecture as a synthesis of Etruscan and Greek temple types, early defensive wall building in Rome and environs, and a range of technologies and building practices that made this architecture possible. City planning in such early Roman colonies as Cosa and Ostia is also discussed, as are examples of the first uses of the arch and of concrete construction, two elements that came to dominate Roman architectural practice. The lecture ends with an analysis of typical late Republican temples at Rome, Cori, and Tivoli.