Discuss monuments such as Old St. Peters, Santa Costanza, Hagia Sophia, San Vitale in terms of the evolution and the convergence of congregational and occasional architecture. Old St. Peters constructed in 320-330 A.D.; Santa Costanza constructed in 350 A.D. in Rome; Hagia Sophia constructed in 537 A.D.; and San Vitale, Ravenna, Italy constructed in 550 A.D. Also, discuss the architectural and decorative program in Hagia Sophia and St. Vitale. Please do not use wikipedia as sources.