Dr. Karl Marx was a missionary in Tibet at the end of the 19th century. Many Tibetan objects kept in the reserves of the American Museum of Natural History (New York City) were collected by him, like the Giant of Great Strength mask and the Bleeding Cup.

Dr. Marx was part of the Moravian mission in Ladakh :

"After Portuguese, the next Christian missionaries arrived during 1855. This time Moravian missionaries were Eduart Pagell and Wilhem Heyde. They had established a Moravian Church and a Christian Mission School at Leh. Later Heinrich Jaeschke, Dr. Karl Marx, A.H. Franke, etc. joined the Moravian mission. They visited village to village for the welfare of people and rendered free education as well medical services. During this period many Ladakhis were converted into Christianity. (…) Dr. Karl Marx was the first trained missionary doctor." [from Famous Western Explorers to Ladakh, Prem Singh Jina, 1995, Indus Publishing (p. 142)].

Marx came to Leh (Ladakh) as a medical missionary in 1887, and participated in the creation of the mission’s first hospital there in 1888 {1}. Aside from his medical activities, Marx seems to have had a scientific interest in the culture of the region where he lived: he was the author of a History of Ladakh ("Three documents relating to the History of Ladakh", published in the Journal of the Asiatic Society of Bengal, vol.LX, part I, Calcutta, 1891). He also translated the Book of the Kings of Ladakh {2}.

The English traveler and writer Isabella L.Bird (1831-1904, born Bishop) reports a trip she has done in Ladakh around 1889 when she met Marx and other Moravian missionaries, in Among the Tibetans (Oxford, 1894) . We learn some biographical information about Marx, who is said to have died of an epidemic a year after her visit (circa 1890). She also describes the Moravian mission’s institutions set in Leh, such as the hospital and school.

"Just outside the Commissioner's grounds are two very humble whitewashed dwellings, with small gardens brilliant with European flowers; and in these the two Moravian missionaries, the only permanent European residents in Leh, were living, Mr. Redslob and Dr. Karl Marx, with their wives. Dr. Marx was at his gate to welcome me. To these two men, especially the former, I owe a debt of gratitude which in no shape, not even by the hearty acknowledgment of it, can ever be repaid, for they died within a few days of each other, of an epidemic, last year, Dr. Marx and a new-born son being buried in one grave." (p.54)

Traditional tea ceremony, Ladakh (Tibet), 1901
Another source infers that Marx was still alive in 1901. This image is shown on the website http://images-missions.net/photos.html with the following legend :
"In 1856 two Moravians missionaries, Eduart Pagell and Wilhem Heyde, make their way into Tibet. They create a mission in Leh (Ladakh) and study the Tibetan language and culture. In 1901, the Moravian bishop La Trobe visits the small Christian community. Pastor Hettasch, Dr Marx and their spouses organise a traditional tea ceremony to his intention. Until this day the small community of Leh, consisting of about a hundred members, is the only Christian presence in Tibet."

An article published in 1920 in the journal of the American Museum of Natural History, Natural History, and entitled "Objects That Symbolize the Common Life in Tibet - With reference to a new and very valuable collection recently obtained by the American Museum from southern Tibet" {3}, documents the acquisition of Marx's collection. The article makes reference to a future exhibition in collaboration with Dr Marx, who had returned to America after sixteen years in Leh.

{1} "In April 1887 Dr. Karl Marx arrived in Leh to take over the hospital and clinic which were partly sponsored by the British Government. Dr. Karl Marx was the first trained missionary doctor to be sent to Ladakh." in Tourism in Ladakh Himalaya, Prem Singh Jina, Indus Publishing, 1994 (p. 42).
{2} "Dr. Karl Marx (...) was able to acquire further, more detailed manuscripts of the Ladakh Chronicle {from the former King of Ladakh}. He found Schlagintweit's version very unreliable when he compared it with the other texts, and begin work on an improved translation. Unfortunately he died when only a third of his work had been printed. His manuscripts and the drafts of his translations of the second and third parts were sent to his brother in Germany." in Recent Research on Ladakh 4 & 5, Henry Osmaston and Philip Denwood, Motilal Banarsidass, 1995 (p. 398).
{3} "Objects That Symbolize the Common Life in Tibet - With reference to a new and very valuable collection recently obtained by the American Museum from southern Tibet", Natural History, edited by Mary Cynthia Dickerson, volume XX, 1920.