In 1715 Ippolito Desideri spent nearly two months in the Himalayan Buddhist kingdom of Ladakh, together with his Portuguese fellow Jesuit and superior, Manoel Freyre. They were well received by King Nyima Namgyal, the Buddhist ruler of Ladakh, and Desideri would have liked to establish a permanent Roman Catholic mission there. However, he was overruled by Freyre who decided to press on to Lhasa. Nevertheless, Desideri's short stay in Ladakh was an important episode because it was there that he had his first encounter with Tibetan Buddhism. This essay reviews Desideri's experiences in the kingdom in the light of recent historical research and with a particular emphasis on the role of his Persian-speaking Muslim guides. He had earlier traveled via Mughal India to Kashmir, and continued to depend on Muslim translators and middlemen until he reached Lhasa. These intermediaries therefore played an essential part in forming his initial views of Ladakh and Tibet to the extent that his exchanges with the king and with local monks may be seen not so much as Buddhist-Christian dialogues but rather as three-way conversations also involving Muslims. None of Desideri's writings mention these Muslim intermediaries by name. From scattered references here and there, this essay attempts to draw them out of the shadows. Keywords: Desideri, Freyre, Persian, Muslim, intermediaries, Kashmir, Ladakh, Mughal, Tibet, Buddhism, Jesuit, missionary.