Show ContentsCastilloe History, Family Crest & Coats of Arms

The Castilloe surname came to Ireland with the Anglo-Norman invasion of the 12th century. They were originally from the Norman family Nangles, or de Angulos, and descended in Ireland from Gilbert de Nangle. Costello and associated variations come from the personal name of a son of Gilbert, Oisdealbhach, whose name consists of the elements "os," which means "deer or fawn", and "dealbhadh," which means "in the form of" or "resembling." The Gaelic form of the surname Castilloe, which predated the Anglicized version of the name, is Mac Oisdealbhaigh. This is the earliest recorded example of a Norman family assuming a Mac surname. The prefix O or Ó has sometimes been erroneously assumed. 1

Early Origins of the Castilloe family

The surname Castilloe was first found in County Mayo (Irish: Maigh Eo) located on the West coast of the Republic of Ireland in the province of Connacht, where they were granted lands by the Earl of Pembroke in the Anglo-Norman invasion of 1172.

Early History of the Castilloe family

This web page shows only a small excerpt of our Castilloe research. Another 138 words (10 lines of text) covering the years 1172, 1500, 1531, 1567, 1571, 1579, 1606, 1803 and 1865 are included under the topic Early Castilloe History in all our PDF Extended History products and printed products wherever possible.

Castilloe Spelling Variations

Medieval scribes and church officials spelt names simply the way they sounded, which explains the various name spelling variations of the name Castilloe that were encountered when researching that surname. The many spelling variations included: Costello, MacCostello, Costillo, Costallo, Kostello, McCostello, Caustello, Costellow and many more.

Early Notables of the Castilloe family

Notable amongst the family up to this time was Guillauame Costeley (1531-1606), Scottish organist and 'valet du chambre du roy' to Henry II and Charles IX of France. 2 Arthur Dudley Costello (1803-1865), was an English-born Irish novelist and travel writer.William Costeley was a Scottish musician, born 1531, settled in France, and was organist to Henri II and Charles IX. Author of a treatise called...
Another 65 words (5 lines of text) are included under the topic Early Castilloe Notables in all our PDF Extended History products and printed products wherever possible.

Migration of the Castilloe family

A great number of Irish families left their homeland in the late 18th century and throughout the 19th century, migrating to such far away lands as Australia and North America. The early settlers left after much planning and deliberation. They were generally well off but they desired a tract of land that they could farm solely for themselves. The great mass of immigrants to arrive on North American shores in the 1840s differed greatly from their predecessors because many of them were utterly destitute, selling all they had to gain a passage on a ship or having their way paid by a philanthropic society. These Irish people were trying to escape the aftermath of the Great Potato Famine: poverty, starvation, disease, and, for many, ultimately death. Those that arrived on North American shores were not warmly welcomed by the established population, but they were vital to the rapid development of the industry, agriculture, and infrastructure of the infant nations of the United States and what would become Canada. Early passenger and immigration lists reveal many Irish settlers bearing the name Castilloe: Honor Costello who landed in America in 1756; Bernard, Cornelius, Edward, Hugh, J.B. James, John, John B. Lawrence, Mark, Michael, Neal, Patrick, Peter, Philip, Thomas, Timothy, and William Costello, all landed in Philadelphia, Pennsylvania between 1833 and 1874.



The Castilloe Motto +

The motto was originally a war cry or slogan. Mottoes first began to be shown with arms in the 14th and 15th centuries, but were not in general use until the 17th century. Thus the oldest coats of arms generally do not include a motto. Mottoes seldom form part of the grant of arms: Under most heraldic authorities, a motto is an optional component of the coat of arms, and can be added to or changed at will; many families have chosen not to display a motto.

Motto: Ne te quaesiveris extra
Motto Translation: Seek nothing beyond your sphere.


  1. MacLysaght, Edward, The Surnames of Ireland. Ireland: Irish Academic Press, sixth edition, 1985. Print. (ISBN 0-7165-2366-3)
  2. Smith, George (ed), Dictionary of National Biography. London: Smith, Elder & Co., 1885-1900. Print


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