What is the origin of the Cassidy surname in Ireland?

Here is the answer given by Bard, the artificial intelligence tool from Google:

The Cassidy surname is believed to have originated in County Fermanagh, Ireland, from the Gaelic name “Ó Caiside,” meaning “descendant of Caiside.” Caiside is an Irish name thought to derive from the Irish word element “cas,” meaning “curly(-haired).” The name Caiside was borne by a prominent family in County Fermanagh, known as the Uí Chaisín, who were hereditary physicians to the Maguires, a powerful Gaelic clan in the region.

Here’s a more detailed explanation of the origin of the Cassidy surname:

The Uí Chaisín family:

The Uí Chaisín family was a sept, a branch of a larger clan, in County Fermanagh, Ireland. They were known for their hereditary medical expertise, providing healthcare services to the Maguires, a powerful Gaelic clan in the region. The family’s name, Uí Chaisín, means “descendants of Caiside,” suggesting that they traced their lineage back to an individual named Caiside.

The name Caiside:

The name Caiside is thought to derive from the Irish word element “cas,” meaning “curly(-haired).” This suggests that the original Caiside was known for their curly hair, a trait that became associated with their descendants.

The adoption of the name “Ó Caiside”:

In the 12th century, a branch of the Uí Chaisín family moved to Devenish Island in County Fermanagh [Ed. note – learn more about the Cassidy connection to Devenish Island]. Over time, they adopted the name “Ó Caiside,” which emphasized their descent from Caiside and their connection to the Uí Chaisín sept.

Anglicization of the surname:

With the arrival of the English and the anglicization of Irish names, the name “Ó Caiside” gradually evolved into various Anglicized forms, including Cassidy, Cassiday, Cassiday, Cassedy, Casadei, and Cassedey. [Ed. note – see our discussion of Cassidy surname variations.]

Spread of the surname:

Over time, the Cassidy surname spread beyond County Fermanagh and across Ireland, particularly to the western and midlands regions. This distribution reflects the migration patterns of the Irish population within the country.

Emigration and global presence:

The Cassidy surname also found its way to other parts of the world, including the United States, Canada, Australia, and the United Kingdom. This global presence is a result of Irish emigration patterns, particularly during the 19th and early 20th centuries.

In conclusion, the Cassidy surname is deeply rooted in Irish history and culture, stemming from a prominent family of hereditary physicians and poets in County Fermanagh. The name’s evolution from the Gaelic “Ó Caiside” to its various Anglicized forms reflects the linguistic and cultural changes that have shaped Ireland over the centuries.

Today, the Cassidy surname carries a legacy of medical expertise, poetic tradition, and resilience, and it is a reminder of the rich tapestry of Irish heritage and its enduring influence on families around the world.

[Ed. note – learn more about the history of the Cassidy’s in Ireland.]