The purpose of this particular essay is to tell a story that, unless I tell it, will probably never be told as an important piece of American history.  This is the story of somebody who is probably the Hudson Valley’s first Jewish physician. 

When I first learned about Dr. Isaac Marks back in 1982, I noticed historians referring to him in several of the local documents.  In a discussion about this “Dr. Marks” with Jewish Genealogist Rabbi Hirschfeld (sp?) of New York City back around 1990, we were unable to determine which of the three possible Isaac Marks the Dr. Marks of Dutchess County could be.  Isaac Marks is first noted in Dutchess County records about the time another physician whom I was researching practiced medicine–Dr. Cornelius Osborn.  Dr. Isaac Marks’s name came up in my search for biographical information on Osborn as part of a transaction Osborn had with a local storekeeper and accountant.    

It ends up Drs. Marks and Osborn were working together, serving New York Governor Clinton, attending to local Foot Soldier John Lane who they had to treat due to some sort of illness.  At first I thought it to be very interesting that a Dutch-English Colonial physician raised in New York like Cornelius would be working alongside a Jewish physician of unknown national and cultural heritage.   That started me along a research path to find out more about who and what Dr. Marks really was.  This study took me more than 25 years to find out the answers to the questions I had at the time, questions like:

  • ‘What kind of person was Isaac Marks?’
  • ‘What did he look like in terms of his apparel?’
  • ‘Why was he sometimes referred to by historians as Dutch or English and other times French?’   
  • ‘How different was his medical philosophy and training from that of Cornelius Osborn?’
  • ”Is he the doctor who originally mentored Cornelius Osborn as an apprentice learning medicine during the 1720s to 1730s?’ 
  • ”If so, then what kind of medicine did Isaac Marks know?’ 
  • ‘Was he the reason Dr. Osborn practiced a form of alchemy (ens veneris) for some of his medicine?’
  • ‘What was his nationality and what type of Judaism faith did Isaac Marks adhere to?’
  • ‘What kind of life did he live in the wilderness of the Hudson Valley?’
  • ‘Why was he in the Hudson Valley so far away from the rest of the Jewish colonists residing closer to Manhattan and Rhode Island?’


Regardless of the color of our skin, the types of clothes we wear, or the forms of religion we practice, a well-trained physician like Dr. Marks would have viewed us as being same sort of individual with the same standard physiological and anatomical features regarding health.  The Jewish physician did not bear the horns that some historians for the time thought Moses might have had (due to some misinterpreted writings used to make a painting).  The relationships between Osborn, Marks or others like the local slaves and Indians was uncertain.  Like most common folks for the time, few really believed in what Jesuit Missionary Father Louis Hennepin had once penned in his description of the American Indians in New France in 1698, suggsting they were the  missing tribe of Israel noted in the Old Testament.   As far as most people were concerned in the former New Netherlands, most of what made us different from each other is how we made use of and respect of our bodies–that vessel we are provided with in order to live out our life. 

This is something that physicians like Isaac Marks would have been more accustomed to thinking than non-Jewish physicians regarding life and longevity.  It was unusual for Jewish doctors, much less Jewish men, to strip themselves of their religious heritage in exchange for defining how they practiced medicine.  Due to local cultural beliefs, knowledge, logic, morees and taboos, Isaac Marks was probably more experienced and familiar with this life process than most other non-Jewish physicians in the immediate region.  He would have adhered to his traditions more than others, even though these were derived mostly from very old beliefs and cultures.   This is what would have made Jewish medicine so different from the other forms of medicine practiced in the immediate region for the time. 

Isaac Marks may have not been so much a blood-letter as some would have hoped him to be.  His way of treating people would have very much been focused on the body’s natural processes, and G-d’s way of defining these processes differently for each and every individual.  Isaac might have listened to the new age preachings for the times that these other physicians had to share, such as the new ways of practicing Alchemy according to George Starkey’s philosophy or the ways to integrate the metaphysics of Boerhaave’s and Jakob Boehme’s teachings into the more modern ways of trascendental thought (if I can apply this term to this time).   No matter what form of medicine Isaac Marks practiced, there were the locals who could understand its metaphysical interpretations, even if it was based on the Qabala and the writings Moses and Maimonides.

For much of history, the Jewish individual, especially the Jewish physician, was made not only a victim of prejudice performed by Christian and Islamic communities, this person also learned to become someone who could camouflage himself to some extent, and manage to keep his or her religious belief system and practice somewhat hidden.  This aspect of each Jewish individual has an impact on their overall life patterns.  It did little to change their overall belief system and philosophy, but it accomplished a lot in terms of concealing who and what they were or represented for decades if not centuries to come.  This means that in the Hudson Valley, Isaac Mark’s individuality and personal philosophy came to play a major role in whatever social interactions he engaged in where he made his personal philosophy (but not religion) well known.  It is for this reason that he risked his own security at one point, allowing a servant escaped from his master’s place to stay there for at least one night, on his way to Connecticut or Canada in search of freedom.  It is also for this reason that even though Isaac Marks left us with little to no description of the kind of medicine that he performed, we are still able to reconstruct the content and nature of his medical philosophy and practice.  Like the Torah and other traditional Jewish texts, traditional Jewish medicine hadn’t changed much during the past centuries.  Be Marks’ education in medicine an event that took place around 1690, 1720 or even as far back in history as the period of Middle Eastern and Muslim reign in much of Europe, much of what Isaac Marks believed in and practiced consisted of much the same basic philosophy and reasoning as those practices engaged in by his mentors of the past.  Even during the 1700s, the Cabala was still the Cabala, Maimonides was still our most important teacher and writer, and the doctor was still a Rabbi first and a Ha-Shem second.  Isaac Marks was a Jewish doctor locked into tradition, his life enhanced just a little by the local modern philosophy in science then developing.  Isaac Marks was Jewish first, and a doctor second.

The History of this Work

I have to begin this work by mentioning that this discovery that Isaac Marks was perhaps the first Jewish Doctor of this region was not made by me but rather by a Dutchess County historian during the early 1900s reviewing the history of medicine and physicians in the Hudson Valley.   Decades later, another similar line of reasoning was played through by a locally famous genealogist, whose extended periods of obsession with every note out there concerning every detail on the local history led him to uncover a small note or two in the historical collections providing us with still more insights into Jewish behaviors in the Hudson Valley some time during the mid 1700s. 

We can add to this work on local Jewish medical history several more limited stories told about Jewish culture and its experiences in the North American setting by reviewing several other American Jewish Colonial history writings, especially those related to the history of medicine in the New World.  Historians and genealogists like to provide whatever details were available to them about Jewish culture along the  Atlantic shoreline and as part of the colonial history of the Carribean and Central and South American communities.  Their information tells us where the bulk of New World Jewish tradition migrated to over the centuries.  Another series of writings on local and national medical history in the colonies gives us just a few mor details about where Jews settled, and for one biography provided, where a Jewish physician was known to settle and the consequences of his Jewry within this historically important American community in the Mid-Atlantic region.

Still, none of these writings provide the details we need to know Jewish medicine during Colonial times.  This information comes to us mostly by studying Jewish history within the European setting.  Thus comes the problems with the complexity of this work. Studying Jewry is not like studying any single country’s culture.  Jews did not have a boundary, natural or political, depicting their dispersion across Europe, Asia, Africa, or around the world.  Even if we knew exactly where Isaac Marks came from, we still would not really know what kind of Jewry he practiced and lived by.   

When I first came upon Dr. Marks and Dr. Cornelius Osborn working side-by-side, due to the unknown source of the alchemical practices contained in Osborn’s book, I speculated that Osborn learned this from Marks.  This seemed to fit the scenario that Marks and Osborn worked together assisting Governor Clinton, with Dr. Isaac Marks the oldest of these two physicians, and Dr. Osborn the younger of the two since he was engaged in the first years of his practice.  Just how old Dr. Marks was still remains an unanswered question. 

Thirty years into this work I believe that Isaac Marks was slightly older than Cornelius Osborn, but any influence he had upon Osborn’s medical philosophy is still questionable.  So Isaac Marks’ story has to be told in the context of what we know is true–the history of Judaism and medicine in Europe and in the Colonies based on all the possibilities that then existed.   Isaac Marks personal history and this history of Jewish medical practice in Dutchess county during the mid- to late 1700s, is a that of a Jewish physician who was either Sephardic, Ashkenazi or Hassidic–the three big Jewish cultures for the time.




Based on historical documents in the possession of several historical sites, libraries and governmental archives, what we know about Dr. Isaac Marks is that he is in fact a physician, and not just any other Colonial Jewish settler making his way about the New York setting.   In a letter written during the mid 1700s, Isaac Marks was also a mohel who performed the Brit Milah or “briss” upon new born children just 8 days of age.  His credentials were more robust than other Jewish leaders in the region.  This meant that he had to frequently travel from one Jewish community to the next, not only in the Hudson Valley between the Dutchess and Westchester county regions, but also to sites as far away as one of the largest Jewish communities in the Northern Colonies located in Newport, Rhode Island. 

As a physician, Dr. Isaac Marks received the respect and support of one of New England’s most respected rabbis, Abrahams Abraham.  It is from Abrahams Abraham’s personal letters about the life and services of a mohel that this part of Dr. Marks otherwise unknown life story can be told.  According to Abraham, Isaac Marks was like him one of the most highly respected Jewish citizens for his time, but he was also a trouble maker.  From these letters we learn that at times Marks was troublesome when it came to voicing his opinions about the social practices of slavery and the rights to practice according of traditional Jewish faith.  Residing within a largely Dutch Protestant-Episcopalian setting at the time, Isaac Marks more than likely suffered due to the mistrust many had towards him, especially if he was abiding by any traditional Jewish beliefs and practices related to the Qabala.  Some of Dr. Mark’s practices, even in the best of circumstances, would in the least result in claims that his beliefs were unique and different from that of the average physician.  Still, in spite of these differences, Isaac Marks was allowed to practice his form of medicine so long as it didn’t impact or involve the neighbors too much. 

But even in the best of the local social settings, many locals might have accused Marks on occasion of being too much in touch with the Devil.  God forbid if Isaac’s resembled anything like that taught by the Qabala, practices more common to Jewish people from Eastern Europe.  This would have been the reason we learn of Marks sometimes being referred to as a French physician, using national identity to conceal his religious identity.  Were anyone to the south of this region to learn about Marks’s training in medicine as a Jew, he may have been accused of practicing some sort of blasphemous demonic skills of the trade, not the skills of a physician, or a traditional Jewish medical and metaphysical practitioners, but rather the practice of “Magick” as it was defined by Satan.  This same accusation had already resulted in the imprisonment of the other Jewish doctor who preceded Isaac Mark, a physician residing in the Mid-Atlantic colonies about this time.   Had any members of the local communities seen Isaac Marks practicing his traditions in the solitude of his home,would they have thought the same?   Some could have claimed that, yes indeed, Isaac was engaged in only -practices under the guidance and leadership of who else? Satan.  Even though the local Dutch metaphysical community might have understood some of the Qabala that Marks’s philosophy and practices were based upon, noting they were not identical with the Christian ideologies born by similar lines of reasoning, these cultural differences were not a threat to Isaac.  A sufficient wall was constructed enabling Isaac to conceal most of his Jewish medical traditions and practices from the Dutch and English.

Socially, we learn more of the particular class of Jewish residents in the county due to legal papers.  Even in the best of the local political and social circumstances, Dr. Marks got in trouble and these problems had to be documented by local courts and justices.  We know some of his life style practices, religious behaviors, and day to day habits, due to this practice of the court.  We can tell from these papers that Isaac Marks ethics created some discomforts with local political and religious leaders because on one of more occasions he had to tolerate spending some time in the local gaol (jail).   Assuming the “Dr. Marks” referred to by Abrahams is the same as the “Dr. Isaac Marks” of Dutchess County, Abrahams’s impressions of Isaac Marks pretty much match the other bits and pieces of scanty evidence out there detailing at least of other encounters Marks had with law officers.  In an encounter he had with the Poughkeepsie sheriff, he was confronted due to claims that he provided refuge for another locally suppressed member of the county–a servant who had escaped his master’s residence and began making his way northwards into Canada.   Early on in Marks’s professional days serving the community at large as a physician, he assisted the New York Governor, George Clinton, by transporting some goods from one part of the community to the next.   On another occasion, he worked alongside Dutch Physician Dr. Cornelius Osborn tending to a medical problem suffered by local British foot soldier John Lane.


Hudson Valley Jewish Medicine, ca. 1745

There are three rules to follow when one is a Jewish doctor in the Hudson Valley during the mid-1700s.   The first is the live your life according to the teachings of Jewish tradition and how they relate to your personal life and belief system.  The second is to learn the traditional Jewish philosophy about health and well-being, including the teachings of Moses, Maimonides, and other famous Jewish physicians.   The third is to learn “modern medicine” as it was being presented at the time of your apprenticeship.  This meant that every Jewish physician during the Colonial years had to learn some traditions that were not taught to their peers or by other religious groups or sects, as well as some traditions that have been taught and retaught to Jews for as long a period of time as the Torah and Talmud have existed. 

The important thing to understand about Isaac Marks and the profession of medicine at the time in Jewish life was that even though, as a physician conversing with other physicians about a particular case, that those doctors working alongside you were practicing a number of the same treatment methods as you as a physician, but also a variety of medical practices not conforming with traditional Hebrew Law.  This defined the differences between Jewish medicine and non-Jewish medicine during the colonial period.  Whereas in some cases, the basic underlying premises for employing some of these methods seemed different, one due to the teachings of alchemists, the other due to the teachings of the Talmud and Torah, everall results were the same in terms of caring for the patient.  Only the physicians’ self-perceived causes for illness and disease were very different from time to time in a philosophical sense.  This meant that to the Christian physicians, the alchemical writings of a Christian alchemist/chemist like Robert Boyle were right, whereas the Kaballistic teachings traditional to some parts of Jewish medicine were not.  It was alright for local physicians to be adherent to the natural philosophical teachings of Jakob Boehme, and irreverent to promote the teachings of the early Jewish naturalist and founder of much later Hassidic traditions and practices, Baal Shem Tov.

As I just noted, Dr.  Isaac Marks was discovered during the early 1900s by a Dutchess County historian, but his underlying history, heritage, philosophy, means of learning and practicing medicine, and general set of social beliefs that he adhered to had to have been very different than those of his partner in medicine, Dr. Cornelius Osborn.  One big question that had to be answered nearly thirty years ago when I began this study was “was Isaac Marks, younger, older or the same age as Dr. Osborn?”  For the next 25 years I went under the assumption that Isaac Marks was either an older physician that Osborn was learning under, or a local physician of similar age to Osborn, but perhaps the “elder” of the two then serving the New York Governor.  The notion that Isaac Marks was that much younger than Osborn seemed pretty much eliminated from my options, due to records of his residency in Poughkeepsie and his apparent age at that time during the Revolutionary War years.

During the Revolutionary War,  Isaac Marks did not work alongside Cornelius Osborn at the Fishkill Hospital.  This may have been because he was too old, not learned enough according to the locals, not exactly a patriot but not exactly a loyalist either, or simply because he was Jewish.   According to historical county documents, as part of some miscellaneous collection, he was apparently someone against slavery, for he is noted in one document as serving as a place for a runaway servant to spend a night during his travels away from his master and this region.

The most revealing evidence came about rather recently regarding Isaac Mark’s background and heritage.  It ends up that Isaac Marks, much like Rabbi Abrahams Abraham, served the lower New England-New York region in performing brisses (Jewish ceremonial circumcision).  In one letter sent to Rabbi Abrahams by a father wishing to have his son brissed, for whom he wanted to raise and prepare for later medical schooling at King’s College, Rabbi Abraham refers the individual to Dr. Marks, who had the same qualifications, though less experience, than he himself.  Since Dr. Marks was causing some sort of problems in the local social settings at the time, he was apparently gaoled and unable to be of service to the father.  According to Rabbi Abraham, Dr. Marks served the same areas and families that he did, focusing on the Westchester County area.  This suggests that Dr. Isaac Marks can be linked to Rabbi Abraham’s routes, which went from Newport, Rhode Island to New York, New York.  But as to what type of Jewish physician Dr. Isaac Marks was–Sephardic or Ashkenazi–requires a more careful review of his possible training and practice and the local and regional Jewish community’s demographic features as a whole.

Encyclopaedia Judaica (1971): “USA”, Vol. 15, col. 1593-1594. Map 1. Main centers of
Jewish population in the U.S., 1800, according to the state borders of today

Currently, the evidence suggests that the Isaac Marks of Dutchess County was most likely an Ashkenazi, either of English or Dutch-English origin.

The related sections of this study of Dr. Marks reviews each of the 3 parts of hist training and philosophy in medicine.  Unfortunately, Dr. Marks left few if any medical documents, so his philosophy of practice remains pretty much uncertain.  What we do know is that Dr. Marks was a Jewish physician practicing both traditional Jewish and that he was trained in, and perhaps practicing, some aspects of non-traditional, non-Jewish “modern” medicine for the time in Hudson valley history.  Dr. Mark’s non-traditional, non-Jewish practices are partially reviewed in the section on Dr. Cornelius Osborn’s history and biography.  Some efforts will be made here to review what aspects of Osborn’s medicine Isaac Marks perhaps didn’t practice.  Isaac Marks did have his own metaphysical beliefs to follow as a Jewish physician, and perhaps practiced some of the teachings of Qabala, much like Cornelius Osborn practiced his own forms of alchemy borne and defined by George Starkey, Robert Boyle, and Hermann Boerhaave.  Another philosophy borne about the time of Isaac Mark’s practice years was the natural philosophy taught by Baal Shem Tov.  Isaac Marks lived in much the same natural setting and this founder of early Hassidism.

Websites and References