The principal discoveries about these later ages have been in the papyri, which have been largely found during the last twenty years. The details of the government and life of the country in the Ptolemaic (305–30 B. C.) and Roman (30 B. C.–640 A. D.) periods have been cleared up; and many prizes of classical literature have also been recovered. The archæology of the Middle Ages in Egypt has also been studied. Many of the Arabic buildings have been recently cleaned and put in good condition, and the splendid collection of manuscripts in Cairo has opened a view of the beautiful art of the thirteenth-fifteenth centuries so closely akin to what was done in Europe at the same time. Egypt is, then, before all other lands, the country of archæology. A continuous history of seven thousand years, with abundant remains of every period to illustrate it, and a rich prehistoric age before that, give completeness to the study and the fullest value to archæological research. MESOPOTAMIA The valley of the Euphrates might well rival that of the Nile if it were scientifically explored, but unhappily all the excavation has been done solely with a view to inscription and sculpture, and no proper record has been made, nor have any towns been examined, the only work being in palaces and temples. The earliest study on the ground was by Rich (1818–20), who gathered some few sculptures and formed an idea of Assyrian art. The French Consul, Botta, excavated Khorsabad (founded 700 B. C.) in 1834–35, and Layard excavated Nimrud in 1845–47; these were both Assyrian sites. The older Babylonian civilization was touched at Erech by Loftus, in 1849–52; and this age has attracted the most important excavations made since, at Tello by Sarzec (1876–81), and at Nippur by Peters and Haynes, of Philadelphia, during the last few years.