Oleg Grabar is professor emeritus in the School of Historical Studies at the Institute for Advanced Study, Princeton, and the Aga Khan Professor of Islamic art emeritus at Harvard University. Among his twenty-odd books is The Dome of the Rock (Harvard University Press, 2006). Photo by: Cliff Moore

At the core of any lasting peace in the Middle East is the Old City of Jerusalem, whose rich and ancient history reflects the diversity of the many religions that consider it sacred.