In the 6th century Byzantine Empire, Emperor Justinian I expanded the empire to its greatest extent during his reign from 527 to 565. During this time, two major architectural works were constructed in Constantinople (now Istanbul): Hagia Sophia from 532 to 537, featuring a massive central dome supported by pendentives; and the Church of San Vitale in Ravenna, Italy from 526 to 547, also employing a central dome and mosaic panels depicting Emperor Justinian and his wife Theodora.