In 1955 the Sultanate of Muscat and Oman, southeast of Saudi Arabia on the Arabian Sea, was a truly medieval Islamic State, shuttered against all progress under the aegis of its traditionalist and autocratic ruler. But it was also nearly the end of an imperial line, for in those days the British Government was still powerful in Arabia. Rumors of subversion and the intrigues of foreign powers mingled with the unsettling smell of oil to propel the sultan on a royal progress across the desert hinterland. It was an historic journey–the first crossing of the Omani desert by motorcar. Jan Morris accompanied His Highness as a professional observer, and was inspired by the experience to write her major work of imperial history, The Pax Britannica Trilogy.