I have been aware of Jost Mertz as an early immigrant almost from the time I began to research people of the Mertz name and I have learned a lot about him over the years. It was always a theory of mine that perhaps he was the younger brother of Johann Henrich (aka John Henry) Mertz, another early immigrant and founder of Mertz Church. Here is a summary of what I learned about Jost.

His is a unique name. Do a google search on the name -- and you basically find just him. Enter it in the search engine of Ancestry.com -- same thing. Every observation appears to be him.

After his 1748 arrival on the ship Patience, he next was named, with wife Anna Maria, at the 1757 baptism at Mertz Church of their daughter Catharina. This was followed by baptisms of three more children in 1758, 1760 and 1761. He died a resident of Rockland Township in 1764.

It was the fact that he so quickly found his way, once in America, to Mertz Church and the fact that he then resided in Rockland Township plus numerous other evidences that the families of Jost and John Henry were close that always made me speculate they were brothers. I now believe it is absolutely proven after three more things came to my attention.

I. There is a German Mertz family living today in Frankenhausen, Germany and their family history is constructed strictly from German records -- knowing nothing about any Mertzes once they came to America. And in their family there was a Jost Mertz born in Germany in 1724, son of Johan Henrich, and the German family’s information is “went to America in 1748, nothing more known of him.” I learned of this in 2009 from a German woman who descends from that Johan Henrich who found my website and wrote to thank me for finding their long lost Jost.

But, interestingly, also in the records of that German family, there was another brother named Johann Henrich Mertz, born, according to those German records, in 1709. The records do not say that he emigrated; on the other hand, they do not say anything more about him. So emigration cannot be ruled out.

The descendants of John Henry Mertz of Mertz Church say he was born in 1708 -- though I’ve never been able to determine how exactly that supposed fact is known. So this coincidence of names and dates added to my belief that John Henry and Jost were brothers.

That would explain why Jost found his way to Mertz Church not long after he came to America.

That would explain why Heinrich Mertz was a witness to Jost’s 1764 will. While there were multiple men named Heinrich Mertz in the various Berks County families, none were old enough then to be a witness other than John Henry himself.

And I think you can make the case that after Jost died so young, that John Henry (and his sons) became closely associated with Jost’s sons -- almost like they became one family. They seem in some cases to have moved to the same place in Northampton County and they possibly stood as sponsors at baptisms of one another’s children.

And that would explain why when John Henry wrote his will in 1786, it was witnessed by Conrad Mertz. There were several adult men named Conrad Mertz from the Longswamp family but logic would strongly suggest it was Jost’s son, Conrad, who was the witness.

Some members of this extended family slowly drifted to different parts of Northampton County starting in, say, the 1770’s. John Henry’s will, though written in 1786 when he said he was of Rockland Township, Berks County, was probated in 1788 in Northampton County. He too must have moved there before his death.

II. Then, in 2014, a man named Dennis Martz joined my Mertz/Martz Y-DNA project at FTDNA, submitted his DNA and told me what he knew of his ancestry. Dennis had traced his ancestry to John Henry Martz (born 1828) who died in 1896 in Illinois — but I was then able to push his ancestry back further and my analysis is that his John Henry was a great-grandson of Jost. So when Dennis’ DNA definitely proved he was related to other Mertzes and Martzes who descended from John Henry Mertz of Mertz Church, the whole case that Jost and John Henry were brothers was greatly strengthened.

III. And now I think the proof is incontrovertible. The Frankenhausen family records show two brothers named Heinrich and Jost. Jost definitely left home for America in 1748 and was clearly the Jost who then arrived America that same year and who then almost immediately became associated with Mertz Church and the family of its founder, Heinrich. DNA proves that Heinrich and Jost were closely related.

Finally, in 2017, a man named Dan Goebel sent me the baptism records for both Johann Jost and Johann Henrich at the Ober-Ramstadt church. They were definitely brothers. Jost was born 19 Nov 1724. Jost is an “original American ancestor” and is designated Y.

The German records also say that Jost had another older brother named Johan George who was born in 1708 and the records apparently say he too came to America, they do not say when. There were several George Mertz in early American records but I knew who most of them were and in any event none ever seemed to have any association with the Mertzes of Mertz Church. So, for a long time, it was a mystery. What happened to this older brother?

Finally, in 2017, with the help of Dan Goebel, I think I can now rule out that any George Mertz of the Frankenhausen family came to America. Dan says there is a record of George marrying in Germany and apparently settling down in a village nearby Frankenhausen. He observes that while the German records do not specifically say that Heinrich went to America, though now we know he did, it is probably that there was simply some confusion at some point as to which of the two older brothers did in fact go, and it was Heinrich who went, not George. I agree.

Jost arrived America on the ship Patience 16 Sep 1748. From 1757, if not before, he lived near Mertz Church.

Jost wrote his will 30 Jan 1764, it proved 10 Apr 1764. He was of Rockland Township. He provided for wife Anna Mary and referred to his “eldest son” but did not name him. His wife Anna Maria and his brother-in-law Richard Hoffman were named Executors. Heinrich Mertz (John Henry I believe) was a witness.

So who was Richard Hoffman? Jost’s mother-in-law was maiden name Hoffman. Was Richard his wife’s uncle and Jost’s use of the term brother-in-law just one of those terms that was more broadly used than the precise way we use the term today? Maybe. I don’t know of any sister of Jost who came to America and married Richard Hoffman. If he were Anna Maria’s brother his name would be Seip. So he must be the husband of a sister of Anna Maria or else an imprecise use of the term.

Someone has put Jost Martz (sic) on find-a-grave with date of death 3 May 1764 which is contradicted by the date his will proved. And they added these comments:

“Burial Source: Christ (Mertz) Cemetery and adjoining Hope Cemetery. Repository: Berks County Historical Society. Page 9. Among the tombstone records compiled by Bernice Sell of Kutztown, were a list of deaths that had been among the papers of a Mr. Amos Breidegam. He entitled this list "Old Church Members of Christ Church, Dryville". The record book in which Mr. Breidegam found these records has not been located. These names were listed under the heading: Names of Deceased/Birth Date and Place/Death Date. Not a positive source for actual place of interment.

I’ve found those Bernice Sell records and indeed that date of death is there apparently from some kind of original church record. I cannot explain the discrepancy. I also agree that nothing in that original record can be taken as a positive indication that Jost was buried at Mertz Church.

Jost and Anna Maria baptized two daughters at Mertz Church: Ana Catharina in 1757 and Maria Margaretha in 1758. On Anna Maria’s tombstone it says she was the mother of two daughters, I assume these two.

For a long time, I never knew what happened to either of them but the story began to emerge in 2019 when I became aware that George Mertz, son of Catharina’s brother Conrad, had moved to and died in Seneca County, New York. To convince myself it really was Conrad’s son, George, and not some other George, who died in Seneca County, I began to look for some carry-through (something known about a person in the old place that matches what we know about him from information of the new place) and it turns out the carry-through for George was his birthday. It was given as 10 Nov 1793 on his baptism record at Zion Lutheran Church in Old Zionsville and it was given as 10 Nov 1793 on a list of burials I found for Jerusalem Cemetery in Fayette, Seneca County.

Jost’s Family Connections to the Keim Family
And now we meet the Keim family. I found a citation to George’s Zionsville baptism in the Ancestry tree of Nancy Tweedie and the record included the fact that the sponsors at his baptism were Johannes and Catharina Keim. That made me curious, who was that couple? Typically, sponsors were a sibling of one or the other parents so was Catharina the sister of Conrad — he had a sister named Catharina — or was Johannes the brother of Margaret, Conrad’s wife?

And then I found another baptism showing that when Johannes and Catharina Keim baptized their son Henry, the sponsors were Henry and Maria Elisabeth Mertz, Henry being yet another child of Jost’s. I felt the two baptisms taken together were pretty solid evidence that Catharina Keim was none other than Catharina, daughter of Jost and sister of both Conrad and Henry.

Then in 2020 the story became even more interesting. I realized that Family Search was showing that George Keim’s wife was Maria Margaretha and I found an 1805 death record for her that said her parents were Joseph and Anna Maria Mertz. I can easily see Joseph as a corruption of Jost, so that seems to be a minor discordant note, especially since, as it turns out, she was buried in the same cemetery as her mother, Anna Maria, and brother, Richard. The burial record gives her birth date as 28 Oct 1757, which contradicts her baptism record at Mertz Church which says 9 Jan 1758, another minor discordant note. But I have seen small errors like that before, so I’m not troubled by either discrepancy.

I believe both of Jost’s daughters married Keims and they were brothers. But there’s still more.

I now believe that Jost’s son, Richard, also married a Keim, likely a sister to the two Keim brothers. The only reference to Richard’s wife I’ve ever found was the 1804 baptism of their son Johannes which gave her name as Maria. But what was her maiden name?

One way to come up with a theory on questions of who someone married is to look at baptisms when that person was a sponsor while still single. In many cases, the other named single sponsor later becomes the spouse. In 1786, Reichart was named as a baptism sponsor when his sister Margaretha and her husband George Keim baptized their daughter Maria and George’s sister Maria Keim was the other sponsor.

Then in 1787, Reichart was named again as a sponsor, this time with Catharine Woeeterin also as sponsor — at the baptism of Catharina Mertz, daughter of Conrad (Reichart’s brother) and his wife Margaret.

Finally in 1788, at Oley Hill, Johannes and Catharina Keim (Reichart’s other sister, I think) had Richard Martin and Maria Keim as sponsors. But there is no evidence of a Richard Martin at that church, could it possibly have been Richard Mertz?

So based on all this, I speculate that Maria, wife of Reichart Mertz, was none other than Maria Keim, sister of Johannes and George Keim — one of whom for sure married a sister of Reichart’s and the other did too (I think).

I have been in touch, subsequently, with Cindy Kimes, a very through Keim researcher and discussed all of this with her. Keim researchers point out that a Maria Keim married Matthias Heydt in 1792 and they are sure that was Maria, sister of Johannes and George. But then what happened to this couple. Isn’t it possible Matthias died young and Maria married second Reichert Mertz? Depending on the timing, she may or may not have been the mother of all of Richard’s children, I’m not speculating on that detail. But I am speculating that Maria, wife of Richard Mertz in 1804, was none other than Maria Keim, sister of Johannes and George.

But we’re not done. There is yet one more Mertz-Keim connection. In the History of Lehigh County by Charles Rhodes Roberts (and others), their profile of the Keim family says this: “Valentine Keim …lived in east Allen township. He died in 1817, aged 33 years, and was buried at the Dryland (Hecktown) church, where he was a member of the Lutheran congregation. His wife, Mary, nee Mertz, died in 1867.”

So who was Mary? Allen Township could be a clue, it was where Henry Mertz, son of John Henry settled. But I think I can rule out that Mary descends from that Henry. The other huge clue is the mention of his burial at Dryland, where Jost’s wife and two children are buried. Cindy Kimes and I have studied all possibilities and believe it is quite possible — speculating again — that Mary was the daughter of Jost’s son Henry. We actually believe he is the best candidate to be her father. Keim researchers do not know the relationship of Valentine to this other Keim family.

The whole concept of the Mærtz Hierarchical Project is to identify every Mærtz named as head of household in any Census up to 1880 and link them back to their original American ancestor. Typically, it was the male named in Census as head of household and of course only males passed on the Mærtz surname to the next generation. So it is quite helpful to be able to be certain as I go generation by generation to know if I truly know the names of all of a man’s sons or whether it’s possible there was one or two I don’t know.

For example, Jost and Anna Maria baptized two sons at Mertz Church: Conrad in 1760 and Reichart in 1762. Was that it? Were there just those two sons? Could there have been more whose baptisms just went unrecorded? How many more?

That is why I consider it so remarkable that on Anna Maria’s tombstone it is truly etched in stone that she had 3 sons and 2 daughters. When I first saw mention of that information, I didn’t realize it was truly on her tombstone as opposed just something someone was saying about her. But it’s there.

So there must have been a third brother and it turns out his identity can be known. When Reichart died, the administrators of his estate were his brothers Henry and Conrad. Henry was the third brother, his baptism went unrecorded, but he existed. And therefore, at least in the case of Jost, we can say absolutely we can name all his sons.

What I’m not sure of is the birth order. It’s possible Henry was the youngest, born in about 1762. But, since he took the lead on filing petitions for Richard’s children, maybe he was the oldest. Perhaps born even before Catharina, so I have guessed 1755 for him.

So we have:

Y1 — Henry
Y2 — Conrad
Y3 — Richard (Reichart)

We know Anna Maria’s maiden name, it was given when she and Jost baptized their daughter Maria Margaretha in 1759.

The book The Ancestors of Margery Ruth Howe tells the story of the Seip family. I have determined that while this book refers to sources and appears to be well researched, everything has to be checked carefully but the breadcrumbs are there to follow.

The Seip family, according to the book, was of Gammelsbach, Germany and there Johan Jacob Seip, son of George Killian Seip and Margaretha Schumpert, born 1697 married Anna Elsiabetha Hoffman 17 Nov 1726. They then had 10 children all baptized presumably at Gaemmelsbach -- since they cite the “Parish Records of Gammelsbach” as their source. It all sounds quite credible.

Among the children were Anna Maria born 6 Mar 1733 and John Jacob born 1 Jun 1744. I believe it is quite a compelling case that these indeed are the two Seips I know — the two intermarried with Mertzes. I know that Rosina Mertz daughter of John Henry was born in 1745 and married Jacob Seip -- so it would seem to be the one born in 1744. And I know that Anna Maria Seip married Jost Mertz (Rosina’s cousin) and her tombstone gives 5 Mar 1733 as her birth date. I have no problem at all with a one day discrepancy.

The book though, says, apparently in reference to John Jacob, the father of these two, that after his father died 15 Jan 1752, he emigrated to Pennsylvania with his sister Anna Maria and his brother Peter (born 1735). But they clearly must mean that Jacob born 1744 came with his sister Anna Maria and his brother Peter.

I think that is most certainly the case. There is no record of the arrival of a Jacob Seip in 1752 or at any other time. However, Peter Seip did arrive on 22 Sep 1752 on the ship Brothers. Typically the lists of passengers on those ships only included males over the age of 16. So neither the younger Jacob nor Anna Maria would have been named but might well have accompanied Peter.

So I believe the older John Jacob, the father, was the one who died back in Germany in 1752 and that led to the emigration of at least three of his children. In the 1790 Census, there was a Peter Sipe in Whitehall Township, Northampton County. So did the whole family start out in Berks County or did somehow only Jacob and his sister Anna Maria go there? I don’t know the answer to that question but it may explain how Jost’s children found their way to Whitehall Township by 1800.

In any event there is a Peter Seip buried in or near Easton (Northampton County) and whose birth date on his tombstone agrees with the Margery Howe book.

Her tombstone is listed by John T Humphrey in Northampton County and it says she had three sons, two daughters.