books.google.ca - In the twilight of the third century C.E., the unity of the Western world was threatened by financial crisis, invasion, and plague. The Syrian city Palmyra had long protected Rome against Persian invasion, but under its queen Zenobia, Palmyra broke away from Roman hegemony. The Roman Empire had never...http://books.google.ca/books/about/Palmyra_and_its_empire.html?id=8kLFfE1qPhIC&utm_source=gb-gplus-sharePalmyra and its empire
