On 24 September 1963, Yaacov Herzog arrived for an appointment at a London clinic. He was not there to see the doctor, but "Charles" – the pseudonym of King Hussein of Jordan. These secret meetings continued for nine years, during which time Herzog also covertly negotiated a agreement with the Imam of Yemen during that country's civil war, wove a web of contacts with Lebanon's Christian community, and met other world leaders. A rabbi, erudite scholar, and gifted diplomat, Herzog was one of the shining stars in Israel's leadership. He served as a close advisor to four Israeli prime ministers, and was ambassador to Canada. Herzog became best known for his public debate with renowned British historian Professor Arnold Toynbee, who had described the Jews as a "fossilized" nation and compared Israel's military actions against Palestinians to Nazi atrocities. Herzog immediately invited Toynbee to a public debate, reminiscent of medieval debates between Jewish and Christian scholars. Herzog's performance bested Toynbee and won international accolades.