Irish Roots
2013 Number 3
Os, Macs and Other Variations in Irish Surnames
By Sean J Murphy
One sometimes hears a roots hunter declare, ‘Oh that couldn’t
be my ancestor, the surname is spelled wrong’. Of course, for a
substantial proportion of surnames there is really no such thing
as an absolutely correct spelling which has remained unchanged
over time. Remember that before the twentieth century many of
our ancestors would have been illiterate or semi-literate, so that
the spelling of their surnames fell to state officials and ministers
of the various religious denominations. The wise genealogist
therefore learns to be aware of the widest possible range of
variant forms of a given surname, in order not to miss a crucial
entry when searching records.
t
he writer still remembers a case
from his early days as a researcher,
when he nearly concluded that a certain
Bartholomew Courtney was not to be
found in County Kerry records, before
persevering and locating the subject
under the form Bat Curnane. Then
there is the question of the prefixes O
and Mac, so characteristic of a majority
of Irish surnames of Gaelic origin,
and it would be fair to say that most
genealogists tend to be alert to the need
to search for names with and without
these prefixes.
Before examining the question of
surname variations it may be useful
to remind ourselves of how surnames
came into being. In Ireland as in other
parts of Europe surnames were in
process of evolution from the tenth
and eleventh centuries onwards, and
the well-worn story that they were
introduced here by an edict of Brian
Boru (depicted in above image) is of
course a myth. Surnames everywhere
can be divided into four main classes,
those derived from an ancestor’s name,
a placename, an occupational name or
a descriptive name (a useful mnemonic
for this is APOD). Most Irish surnames
of Gaelic origin fall into the first or
ancestral class, indicated as we shall see
by the prevalence of the aforementioned
O and Mac prefixes. Furthermore, some
surnames are monogenetic, that is, they
had a single point of origin, while others
are polygenetic, arising independently
in different places.
This last ‘mono-poly’ distinction should
enable us to avoid another romantic
pitfall, namely, the idea that the Irish
like their Scottish cousins were and are
divided into clans, each one equipped
with a surname/clan-name, a ‘family
crest’, a real or potential chief, and
latterly even a tartan available from
canny Scots merchants eyeing the
potential Irish diaspora market. As
the writer has so often pointed out,
Eoin MacNeill, Edward MacLysaght
and other scholars did not favour the
use of the anglicised term ‘clan’ in the
Irish context, MacLysaght in particular
always using the alternative term
‘sept’. While ‘clan’ comes from the
Gaelic word ‘clann’ meaning ‘family’,
‘sept’ is reckoned to be derived from
‘sliocht’, another of a large number of
Gaelic terms indicating progeny, others
including ‘fine’, ‘muintir’ and ‘síol’.
Take for example the writer’s surname,
Murphy, Gaelic Ó Murchadha, the
most common in Ireland. Rather than
being the name of one undifferentiated
‘clan’, Murphy refers to unrelated septs
which originated in Cork, Roscommon
and Wexford, while ongoing serious
genetic analysis may identify other
probable origin points as well. Other
prominent Gaelic surnames are also
polygenetic, for example, O’Kelly/Ó
Ceallaigh, referring to septs historically
located in Galway, Derry, Laois, Meath
and even Wicklow, and O’Connor/Ó
Conchobhair, the name of unrelated
septs in Connacht, Kerry and Clare.
Interestingly, the great Munster sept of
O’Sullivan/Ó Súileabháin is considered
to be monogenetic, although divided
into different sections or sub-septs, and
it will be interesting to see if ongoing
genetic analysis alters this view of the
surname’s uniqueness.
Whence then came O and Mac, the first
usually followed by an apostrophe in
English and the second abbreviated to
Mc? The Gaelic prefix Ó, archaic form
Ua, originally meant grandson of the
8
individual whose name followed, while
the prefix Mac meant son of a specific
individual, but in time both prefixes
came to indicate descent from named
individuals. A caution is necessary
here, in that in Ireland as in Scotland,
some individuals may have adopted the
surnames of their overlords, so that not
all O’Briens necessarily have the blood
of the great Brian flowing in their veins,
while a few may be Bryans in disguise
or occasionally even O’Byrnes. The use
of the apostrophe after O is due to an
English error, confusing the abbreviation
of ‘of’, eg, Glen O’ the Downs, John
O’Groats, with the Gaelic Ó, and indeed
in older records the abbreviation M’ may
also be found for Mac.
Significantly, the surname O’Brien/Ó
Briain arose in the time of the grandsons
of Brian Boru, while MacCarthy/Mac
Cárthaigh is a good example of a Gaelic
surname formed using the second
prefix. There have been some efforts
to recast anglicised forms of Gaelic
surnames by leaving a blank space
between the O and Mac prefixes and the
name proper, but as in the wake of the
Mac Carthy Mór hoax this perhaps gives
the appearance of claiming a chiefship,
the practice has not found much favour.
While the Scots used the prefix Mac
to form surnames, they rarely if ever
used O, and we can dispose of the
notion that all or most Mac surnames in
Ireland must have a Scottish connection.
Sometimes it may be difficult to decide
if a surname is of indigenous Irish or
Scots settler origin, especially in Ulster,
for example the names MacAuley and
MacKinney.
There is a popular view that, simply put,
the use of O and Mac was discouraged
or even legally prevented under English
rule in Ireland, and that the prefixes
were restored in the course of the
national revival commencing in the late
nineteenth century. Although there was
medieval legislation requiring the Irish