Eighteen miles south of modern Baghdad in Iraq lies the site of Seleucia on the Tigris, which rose, flourished, and dwindled away between 307 BCE and 215 CE-roughly contemporary with Karanis in Egypt. Seleucia's foundation was part of the Hellenizing of the Near East, the ultimate result of Alexander's campaigns. Lying at the confluence of the Tigris River and a major canal from the Euphrates, Seleucia was a vital trading center and presided over the exchange of goods from Central Asia, India, Persia, and Africa. Excavations were begun at Seleucia December 29, 1927, by Professor Leroy Waterman of the University of Michigan and continued for six seasons until 1937. Seleucia's architecture, according to Dr. Waterman, represents a "missing link" between Hellenistic and Sassanian styles that shows the results of blending Greek with Eastern elements.