Short answers, pulled from the story.
Michael Rostovtzeff was a Russian historian who lived from 1870 to 1952 and produced major works on ancient Roman and Greek history. He served as president of the American Historical Association in 1935 and was one of the first scholars to systematically combine archaeological evidence with literary sources. He is best known for The Social and Economic History of the Roman Empire, published in 1926.
Rostovtzeff argued that the Roman Empire collapsed in the third century A.D. because of an alliance between the rural proletariat and the military against the urban middle class. The theory was shaped by his own experience fleeing the Russian Revolution. The academic community largely rejected it as a projection of his personal experience onto ancient history, though the scholarship inside the book impressed contemporaries.
Rostovtzeff taught at the University of St. Petersburg from 1898 to 1918. After emigrating to the United States in 1920, he accepted a chair at the University of Wisconsin-Madison before moving to Yale University in 1925, where he taught until his retirement in 1944.
Rostovtzeff oversaw the excavations at Dura-Europos, a ruined city on the Euphrates, as part of his role directing all of Yale University's archaeological activities. His findings there were published in Dura-Europos and Its Art in 1938.
Rostovtzeff wrote Iranians and Greeks in South Russia, published by Oxford's Clarendon Press in 1922, which examined cultural exchanges between Iranian nomadic peoples and Greek colonists along the northern Black Sea coast. He followed that with Skythien und der Bosporus in 1925, extending his analysis into Scythian material culture.
Rostovtzeff is believed to have coined the term "caravan city," referring to desert trading settlements that served as commercial and cultural crossroads. He developed the concept in his book Caravan Cities, first published in book form in Paris in 1931 and then by Oxford's Clarendon Press in 1932.