Show ContentsO'Cassidie History, Family Crest & Coats of Arms

Irish names tend to vary widely in their spelling and overall form. The original Gaelic form of the name O'Cassidie is Ó Casaide. 1

Early Origins of the O'Cassidie family

The surname O'Cassidie was first found in Fermanagh (Irish: Fear Manach) in the southwestern part of Northern Ireland, Province of Ulster, where the Irish sept claims direct descent from the Irish King Colla da Crioch who was banished from Ireland in 327. 2

Early History of the O'Cassidie family

This web page shows only a small excerpt of our O'Cassidie research. Another 96 words (7 lines of text) covering the years 1143 and 1740 are included under the topic Early O'Cassidie History in all our PDF Extended History products and printed products wherever possible.

O'Cassidie Spelling Variations

Pronunciation, rather than spelling, guided scribes and church officials when recording names during the Middle Ages. This practice often resulted in one person's name being recorded under several different spellings. Numerous spelling variations of the surname O'Cassidie are preserved in these old documents. The various spellings of the name that were found include Cassidy, Cassady, Cassiday, Cassedy, Cassedey and others.

Early Notables of the O'Cassidie family

More information is included under the topic Early O'Cassidie Notables in all our PDF Extended History products and printed products wherever possible.

Migration of the O'Cassidie family

A massive amount of Ireland's native population left the island in the 19th century for North America and Australia in hopes of finding more opportunities and an escape from discrimination and oppression. A great portion of these migrants arrived on the eastern shores of the North American continent. Although they were generally poor and destitute, and, therefore, again discriminated against, these Irish people were heartily welcomed for the hard labor involved in the construction of railroads, canals, roadways, and buildings. Many others were put to work in the newly established factories or agricultural projects that were so essential to the development of what would become two of the wealthiest nations in the world. The Great Potato Famine during the late 1840s initiated the largest wave of Iris immigration. Early North American immigration and passenger lists have revealed a number of people bearing the name O'Cassidie or a variant listed above: Patrick Cassidy who settled in Rhode Island, and later moved to Norwich in Connecticut, where he became one of America's first surgeons. Edward, Hugh, James, John, Patrick, Thomas and William Cassady who all arrived in Philadelphia between 1840 and 1865.



The O'Cassidie 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: Frangas non flectes
Motto Translation: Thou may'st break, but shalt not bend me.


  1. MacLysaght, Edward, Irish Families Their Names, Arms and Origins 4th Edition. Dublin: Irish Academic, 1982. Print. (ISBN 0-7165-2364-7)
  2. O'Hart, John, Irish Pedigrees 5th Edition in 2 Volumes. Baltimore: Genealogical Publishing Company, 1976. Print. (ISBN 0-8063-0737-4)


Houseofnames.com on Facebook