Introduction
When I first began my genealogical journey, I considered myself a competent researcher with knowledge, skills, and abilities gained from years of academic studies in civilian and military schools as well as experience gained from various military assignments that required researching duties. However, I know that while my research skills would prove useful in my genealogy research, I also recognized I was a novice at genealogy and had much to learn about the field.
One fact that I had to learn was many surnames, such as Cosgrove, have variants and deviants. Its critical to understand the differences between the two forms. According to the Guild of One-Name Studies (https://one-name.org/variants-and-deviants/), a variant is “a name spelling which varies from the primary spelling used by the person’s ancestors and which is:
- A name spelling that the person was known to have used, through signature evidence on wills, marriage bonds, etc. or other document originating from the individual concerned, or
- A name spelling used by officials on a consistent and persistent basis over a period of years.
The Guild defines a deviant as “another spelling recorded, including cases where the spelling occurs in official records, but only randomly and inconsistently.
Unaware of surname variants and deviants, I began my research into my Cosgrove family line by looking specifically for other “Cosgrove” families. I completely dismissed the possibility that my family could have been known as or used a different surname variant, such as Cosgrave or Cosgriff, at any point in time. Thankfully, I recognized my ignorance early on and did not allow it to deny my ability to ultimately trace my family line back to Limerick City.
Through some much-needed assistance from fellow genealogists, I eventually found the one key document I needed to break down my brick wall: the 1871 Limerick marriage record for my third great-grandparents, John Cosgrove and Teresa Dunn. The record served several research purposes: 1) it brought my Cosgrove family from Boston back to a specific geographic location of origin in Ireland; 2) it listed both John’s and Teresa’s fathers (John’s father’s name was new to me, whereas the listing of Teresa’s father’s name on the record was the same name listed on her 1890 Watertown Death Certificate); and 3) it led me to other much needed records that allowed me to build out both my Cosgrove and Dunn family lines (I also learned at this time that the surname Dunn had a variant as well: Dunne).
As I collected and analyzed various birth, baptism, and death records for John and Teresa’s children, I was struck by the different ways their last name appeared in records: Cosgrove, Cosgrave, and Cosgriff. Out of curiosity, I reviewed other “Cosgrove” families in Limerick and discovered that their last names varied from record to record as well. Some families’ last names were spelled consistently (say Cosgrave) and others were spelled as Cosgrove, Cosgriff, Cosgriffe, and Cosegrave (as examples) across different records. Some were likely variants and others were likely deviants as certain spellings were seen in only one document (such as Cosegrave, a very uncommon spelling of the surname, thus likely a deviant surname).
I was most surprised about was how often a father’s last name may be spelled Cosgriff but the child’s last name was spelled Cosgrove or Cosgrave on the very same birth or baptism record…..or a groom’s name was spelled Cosgrove but one of the father’s or witnesses’ surnames were spelled Cosgriff.
When I transitioned most of my free time from my own genealogy research to setting up and managing our Cosgrove one-name study and its DNA project, I began an out-reach campaign to recruit new members to our study. I made sure to cast my net far and wide by reaching out to Cosgroves, Cosgriffs, Cosgraves, Coskreys, Coskerrys, McCuskers, and McCoskers (and others as well). On more than one occasion, I had some of these people tell me (some adamantly so) that they were “Cosgraves” or “Cosgriffs” and not “Cosgroves” while others told me their Cosgrove families had descended from “Cosgriffs.” I found it simply fascinating how people viewed their surnames both in the present as well as in the past. I also realized I needed to convince some people that our different surnames were actually variants of the others and that they had a place and role in our surname project if they so desired.
What Does My Current Research Reveal?
As part of the surname study, I have been collecting information from various records collections on Cosgrove families. Records to date include birth, marriage, and death records; baptisms; census records; and land and tax records. I have analyzed over 8,000 records to date. While I haven’t conducted any formal statistical analysis of my findings, I can summarize (with a fair degree of confidence) some of the trends I have seen regarding the usage of the Cosgrove surname and its variants:
- The spelling for some families’ surnames were very consistent across different types of records.
- The spelling for other families’ surnames were wildly inconsistent within and across records collections.
- It is not entirely uncommon for families to have more than one surname variant listed for their family names within and across records collections.
- Some counties, civil registration districts, and church parishes seem to have a higher occurrence of one form of spelling for the surname (predominately Cosgrove or Cosgrave, and to a lesser extent Cosgriff) than other forms of spelling.
- I have even found a couple of instances where surnames were transcribed differently on different genealogy sites found on the same record. For instance, Site A and Site B may have the same baptism record in their Ireland Roman Catholic Baptism Records. The volunteer who transcribed the record for Site A may have spelled the family name as Cosgrove whereas the volunteer from Site B spelled it as Cosgrave. Transcription errors could also explain why some transcriptions have the father’s or mother’s surname spelled differently than the child’s on the same record.
Here are some examples of my findings of birth and baptism records from County Limerick (Chart 1 and 2) as well as an example of a difference in spelling of a witness’ last name between a civil record and church record for the same marriage from County Tipperary (Chart 3):
| Last Name | First Name | Birth | Father | Mother |
| Cosgry | Eugene | 3 Mar 1835 | John Cosgry | Ellen Tierney |
| Cosgry | Thomas | 5 May 1837 | John Cosgry | Ellen Tierney |
| Cosgry | Hanora | 18 Apr 1842 | John Cosgry | Ellen Tierney |
| Cosgriff | Denis | 14 Nov 1844 | John Cosgriff | Ellen Tierney |
| Cosgriff | Michael | 2 Aug 1847 | John Cosgriff | Ellen Tierney |
| Last Name | First Name | Birth | Father | Mother |
| Cosgriff | Mary Bridget | 6 Feb 1872 | John Cosgriff | Teresa Dunn |
| Cosgrove | Patrick Michael | 30 Sep 1873 | John Cosgrove | Teresa Dunn |
| Cosgrave | Catherine | 24 May 1875 | John Cosgrave | Teresa Dunn |
| Cosgrove | Matthew | 17 Aug 1876 | John Cosgrove | Teresa Dunn |
| Cosgrove | Joseph | 15 Mar 1878 | John Cosgrove | Teresa Dunn |
| Cosgrave | Jane | 3 Feb 1880 | John Cosgrave | Teresa Dunn |
| Cosgrove | John | 6 Feb 1880? | John Cosgrove | Teresa Dunn |
| Cosgrave | Joseph/John | 9 Apr 1881 | John Cosgrave | Teresa Dunn |
| Cosgrave | Teresa Mary | 14 Sep 1882 | John Cosgrave | Teresa Dunn |
| Cosgrove | Teresa Mary | 16 Sep 1882 | John Cosgrove | Teresa Dunn |
| Groom Name | Bride Name | Wedding Date | Witness #1 |
| Cosgrove | Collins | 27 Feb 1867 | John Cosgriff |
| Cosgrove | Collins | 24 Feb 1867 | John Cosgrove |
As you can see in the second chart, the family’s surname appears as Cosgriff, Cosgrove, and Cosgrave across the various birth and baptism records. I know this family well as it is my Cosgrove family from Limerick City. When I first located Mary Bridget’s 1872 birth and baptism records, I initially dismissed the records because I was looking for a Cosgrove family, not a Cosgriff family. Forget that her middle name was different from what I had found in a Boston record along with the fact that the name “Patrick Michael” was the actual given name for my 2nd great-grandfather, John Patrick Cosgrove. Theresa Mary, the last of the children born in Ireland prior to the family’s immigration to the U.S., had two birth records filed in Limerick City, each with a different surname spelling. To say I was confused by the difference in given names and surnames would be an understatement. Other evidence led me back to this family and once I looked at all of the records objectively, I realized I had found my family. Thankfully, DNA testing of descendants of my 3rd great-uncles and aunts were shown to be high DNA matches with my uncle and I.
One of the challenges many genealogists and family historians encounter is the listing of different surnames for what appears to be the same ancestor, whether the listings of the surnames are found in family trees made by earlier generations or found in civil and church records or both. In many cases, the experienced researcher will more or less be able to figure out the Robert Cosgrave referenced in a cousin’s family tree or civil record is the Robert Cosgrove found in his or her own family tree. It can be a bit more complicated when we have instances of the surnames McCusker, McOscar, McCosker, and Cosgrove. Some sources exist that suggests these names are variants of one another. I have been in some spirited discussions with people who carry these surnames on the validity of whether or not Cosgrove is a valid surname variant for any of those three names. I have yet to draw my own definitive conclusion on the matter. I do know that I have two Y-DNA groups in my surname project that include two Cosgroves and a McOscar in one…..and four Cosgroves and a McCusker in the other. In other words, the two Cosgroves and the McOscar appear to be distant Y-DNA cousins as are the four Cosgroves and the one McCusker.
The YDNA results could be interpreted in different ways because the sample size is SO SMALL. The YDNA results could indicate a possible surname switch somewhere along the paternal line within each group or we could be looking at two distinct, but genetic related clans in which a Cosgrove Clan and a McCusker/McOscar clan descended from the same paternal ancestor over a 1,000 years ago. A third option is some government and or church authorities deemed the surnames to be valid variants of one another, hence why the same person may be found as a McCusker in one record and a Cosgrove in another. More Y-DNA testing of men who carry these surnames along with additional research across different records collections could help provide stronger evidence that we can use to draw a more definitive conclusion.
Impact of Anglicization of Gaelic Family Names
We have to keep in mind that our distant ancestors once had Gaelic names and it was only in the 1500s and 1600s that the native Irish were mandated to use Anglicized surnames by English authorities. Often times, authorities “gave” the families their new names and these names evolved and changed for reasons sometimes unknown. We also have to keep in mind that some parts of the population in the 1500s, 1600s, and 1700s were not as literate as others, so some of our ancestors may have been entirely dependent upon church officials and civil servants to record their names in records for them, which in itself could explain why surnames appear different from record to record. Thus, the possibility exists a Cosgrove could have once been a McCusker or Cosgrave, but for whatever reason, his surname was written as “Cosgrove” in various public records long enough that the name “stuck” over the generations.
What Does a Genealogist Do When Confronted with this Situation?
My biggest piece of advice is keep open the possibility that your family’s surname may have been spelled differently than what it is today. Of course, if you have a plethora of records dating back to the early to mid-1800s that show your family’s surname was spelled with a high degree of consistency, then you may be able to limit your search for additional records focused on that specific spelling of the family’s surname. However, if you are looking to overcome a brick wall that has existed for quite some time, consider the following:
- Your family could have been listed in records under a surname variant(s). When researching records collections both in the country in which you currently reside and, in your family’s native country, ensure you do not purposely ignore records that may list surname variants as family’s last name as opposed to the way your family currently spells its name. You could be overlooking the one or two records you need to break through your brick wall. Remember, depending on where your family lived in Ireland, your Cosgraves could have very well been recorded as Cosgroves or Cosgriffs or Coskreys. In my case, my own family was record as Cosgroves, Cosgraves, and Cosgriffs.
- Consider conducting a broader review of records for other Cosgrove families in the same area where your family is suspected or known to have lived. If you are not sure whether your family could have been known by another surname variant(s), consider taking some time to look at records for other Cosgroves in the same parish or civil registration district. As stated earlier, I have noticed trends in certain parishes and registration districts where surname spellings for Cosgrove families were more consistent whereas they were inconsistent in other localities. If you notice a trend that spellings for family names varied in the same area as where you suspect or know your family was from in Ireland, then you may want to explore the possibility your family may have been recorded under a surname variant(s).
- Be cautious using other people’s family trees as references. I lost track how many times I have had people tell me that their family trees were built on very strong evidence and generations worth of family records…….only to tell me a few years later they discovered mistakes or discrepancies made by earlier generations of family historians. It happens. We are human and we make mistakes. If you find your “ancestor” listed in another person’s tree under a different surname variant, use caution. Don’t rush to conclude the person’s tree is correct or that this is in fact your ancestor. You still need to conduct research using reliable and credible record sources to draw a reasonable conclusion that your ancestor was listed in records under a surname variant. Don’t go off of an assumption simply out of frustration with your brick wall. Don’t let your frustration and emotion get the best of you!
- Assess whether YDNA testing could assist you in your research. Currently, our DNA project includes 19 men who carry one of our recognized surname variants and who have taken a Y-DNA test. We have one genetic group that includes a McCusker and four Cosgroves; a genetic group that includes a Cosgrave and a Coskrey; a genetic group that includes a Cosgrave, Cosgrove, and Cosgriff; and a fourth genetic group that includes two Cosgroves and a McOscar. While it can be reckless to draw definitive conclusions on such a small sample size, initial results do show that surname spellings do vary across genetic families, an insight that is consistent with findings from the records and literature reviews. As more men conduct Y-DNA testing, we may be able to use our DNA evidence to help draw a more definitive conclusion on how frequent surname variants appear among specific Cosgrove families.
Final note
On a final note, genealogists and family historians who have conducted research into our shared surnames’ history have likely read older historical texts such as Rev. Geoffrey Keating’s History of Ireland (specifically Vol III that lists various genealogies of the Ancient Irish Clans), John O’Hart’s Irish Pedigrees, and Rev. Patrick Woulfe’s Irish Names and Surnames. Many of the authors have documented the origins of some of the old Cosgrove families from around the 800-1200 AD period in Ireland in their respective books. Most of them have included the different surnames from which the families were later known by to include their known variants. Thus, the idea that a Cosgrove family may be known by more than one surname variant has existed since at last the mid-1600s when Rev. Keating was known to have written his History of Ireland series.
So for my fellow genealogists and family historians, regardless if your family spells its surname differently today than it did two hundred years ago, your surname IS your family name and any variation in its spelling found in earlier generations is just another fact to include in your family’s history.