Located in the marshes of southern Mesopotamia, in modern-day Iraq, Nippur was one of the most sacred cities in the ancient Middle East. Between 1889 and 1900, the University of Pennsylvania was the first American institution to carry out archaeological excavations in this region. The expedition to the site was organized by John P. Peters, funded by the Babylonian Exploration Fund, and directed by Peters and Herman V. Hilprecht. It revealed a multi-layer site with a long and complicated history, and, most significantly, a library of inscribed cuneiform tablets that have formed the basis of our understanding of the first literate society in the world, the Sumerians.