Although the monarchs of the Third Dynasty of Ur (Ur III) ruled over southern Mesopotamia for only about a century (ca. 2112–2004 BCE), they had a disproportionate influence on later literature in the Old Babylonian Period (ca. 2004–1595 BCE). In fact, many of our surviving copies of Sumerian literature stem from school texts of this later period, when Sumerian was no longer a spoken language but was used for scholarly enterprises. Among the copies of Sumerian literary texts from this time are a group of twenty-two letters written to or by three kings of the Ur III dynasty—Shulgi, Shu-Sin, and the last king, Ibbi-Sin. About half of these letters were excavated at major sites in southern Mesopotamia (mostly Ur or the religious and scholastic center, Nippur). The other half are in museum collections; the original find spot is unknown.