Show ContentsCostolo History, Family Crest & Coats of Arms

The Costolo 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 Costolo, 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 Costolo family

The surname Costolo 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 Costolo family

This web page shows only a small excerpt of our Costolo 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 Costolo History in all our PDF Extended History products and printed products wherever possible.

Costolo Spelling Variations

Names were simply spelled as they sounded by medieval scribes and church officials. Therefore, during the lifetime of a single person, his name was often spelt in many different ways, explaining the many spelling variations encountered while researching the name Costolo. Some of these variations included: Costello, MacCostello, Costillo, Costallo, Kostello, McCostello, Caustello, Costellow and many more.

Early Notables of the Costolo 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 Costolo Notables in all our PDF Extended History products and printed products wherever possible.


United States Costolo migration to the United States +

Irish immigration to North American began in the late 18th century as many Irish families desired to own their own land. This pattern of immigration grew slowly yet steadily until the 1840s. At that time, a failed crop and a growing population in Ireland resulted in the Great Potato Famine. Poverty, disease, and starvation ravaged the land. To ease their pain and suffering the Irish often looked upon North America as a solution: hundreds of thousands undertook the voyage. Their arrival meant the growth of industry and commerce for British North America and the United States. For the individual Irishman, it meant survival and hope, and the opportunity for work, freedom, and ownership of land. The early immigration and passenger lists revealed many bearing the name Costolo:

Costolo Settlers in United States in the 18th Century
  • John Costolo, who arrived in Boston, Massachusetts in 1764 3
Costolo Settlers in United States in the 19th Century
  • Michael Costolo, aged 23, who arrived in Philadelphia, Pennsylvania in 1856 3

Australia Costolo migration to Australia +

Emigration to Australia followed the First Fleets of convicts, tradespeople and early settlers. Early immigrants include:

Costolo Settlers in Australia in the 19th Century
  • Mary A. Costolo, aged 18, a farm servant, who arrived in South Australia in 1854 aboard the ship "Lord of the Isles" 4

Contemporary Notables of the name Costolo (post 1700) +

  • Dick Costolo, American businessman, former CEO of Twitter (2010-2015)


The Costolo 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
  3. Filby, P. William, Meyer, Mary K., Passenger and immigration lists index : a guide to published arrival records of about 500,000 passengers who came to the United States and Canada in the seventeenth, eighteenth, and nineteenth centuries. 1982-1985 Cumulated Supplements in Four Volumes Detroit, Mich. : Gale Research Co., 1985, Print (ISBN 0-8103-1795-8)
  4. South Australian Register Monday 14th August 1854. (Retrieved 2010, November 5) Lord of the Isles 1854. Retrieved http://www.theshipslist.com/ships/australia/jamesfernie1854.shtml


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