Cassidy is an ancient Irish surname which has also become popular as a first name.
It comes from the old Gaelic name ‘O’Caiside’. The name O’Caiside was made up of two separate, parts. The ‘O’ prefix indicated that the name belonged to a ‘descendent of…’, and ‘Caiside’ comes from the Gaelic word ‘Cas’ which means ‘curly hair’.
It would have originally been used as a nickname for people with curly hair and eventually became a surname. The descendants and followers of the original clan leader ‘Cas’ would have taken the name O’Caiside.
Prominent in Co Fermanagh
The O’Caisides were an important clan in Ireland. They were particularly prominent in Co Fermanagh and the other Ulster counties. They were well respected and highly intelligent. For hundreds of years during the medieval period they worked as doctors and physicians to the Maguire clan who were Kings of Ulster.
They were also prominent in religion, literature and the arts. The O’Cassidys were famous as a highly educated family up until the 19th century.
Rory O’Cassidy, who was Archdeacon of Clogher, is one of the people who contributed to creating The Annals of Ulster. The Annals of Ulster was a record of events in medieval Ulster and was compiled in the 15th century.
Video of the story of the Cassidy name
Supporters of Home Rule for Ireland
The Cassidys were also known as a patriotic family who believed in Home Rule for Ireland. William Cassidy was a politician who founded the United Irishmen of America. His organisation aimed to end the British rule over Ireland and even used its power to attempt to stop the USA from helping Great Britain in the two World Wars.
Famous Cassidys throughout history
Natalie Cassidy is an English actress. She is famous across Britain and Ireland for her role of Sonia Jackson in the British soap EastEnders. She started out as a child actress and remained in the soap for over a decade before turning to theatre and other TV work.
Ted Cassidy was an American actor who was famous for his role as Lurch, the Butler on The Adams Family. He was also the voice of the incredible Hulk in the 1970s.
Giolla Moduda O’Cassidy was a poet in the 12th century. He is the earliest person in history to have his surname ‘O’Cassidy’ in public records.
Butch Cassidy was an American outlaw in the Old West who was notorious as a train and bank robber. He remains well known to this day thanks to movies such as Paul Newman’s Butch Cassidy and the Sundance Kid. However, his real name was Robert Parker so he is unlikely to be related to the Cassidys.
Eva Cassidy was a soul singer from Maryland, USA. She released an album of duets with Chuck Brown as well as a live album. She tragically died aged just 33 and only recorded one solo studio album.
Since her death, her unreleased recordings as well as compilation albums have gone on to sell millions of copies.
Elaine Cassidy is an actress from Co Wicklow, Ireland. She has appeared in several movies such as And When Did You Last See Your Father, Disco Pigs and Calvary.
Katie, David and Jack Cassidy
Katie Cassidy is an actress from Los Angeles, California. She has appeared in numerous films including Take, Click and Monte Carlo. Her father, David, and grandfather, Jack were also well known actors.
David has appeared in several movies and TV shows and made his name in the 1970s playing the role of Keith Partridge in the Partridge Family. He also had a successful music career.
Jack was a successful actor on stage, film and TV. He won a Tony award for his role in the Broadway play, She Loves Me.