Magner is one of the smallest Irish clans with only a few thousand members living around the world today. The clan was founded by Sir William of Magnel, a Norman knight who came to Ireland in 1183 as part of the Norman invasion of Ireland in the late 12th Century A.D. William Magnel built a castle in the site of a pre-existing Celtic Motte-and-bailey castle along the Keatra River in Northern County Cork, and established a Norman settlement that became known as Magnel's town, and eventually Magnelstown. The name, "Magnel" was difficult for speakers of the local Irish dialect to pronounce, and the name evolved into "Maingneir," which was later shortened to "Magner." The castle and the town it supported both became known as "Castlemagner." Castlemagner remained in the hands of the Magner clan until 1652, when the Magners were dispossessed of their lands during the Cromwellian conquest of Ireland. A local legend tells how the contemporary inhabitant of the castle, one Robert Magner, was visited by Oliver Cromwell as part of an inquest related to the Parliamentarian reconquest of areas that had taken part in the Irish Rebellion of 1641. Cromwell is said to have asked Robert Magner what was so special about the Magners that their lands should be spared confiscation, to which Robert Magner is said to have replied, "It is easy for dogs to walk on the graves of lions!" an insult that implicated Cromwell's commoner origins. A few days later, Robert Magner received a sealed letter from Cromwell via one of his servants, with instructions to show the letter to the local magistrate. Being suspicious, Robert Magner unsealed the letter to find that, instead of Cromwell's decision as to whether his lands would be confiscated, the letter merely stated "Hang the bearer." Robert Magner is said to have resealed the letter and given it to someone loyal to Cromwell and then fled the country with his family. Other members of the Magner clan continued to live in both County Cork and County Limerick, but many emigrated over the succeeding centuries to the Americas, Australia and Europe. One branch of the Magner clan established a farm in Fairfax County, Virginia, near Washington, D.C. in the late 1700s, as well as St. Mary's Catholic church. The church was used as a hospital Clara Barton during the Civil War to treat soldiers wounded at the battle of Bull Run. Castlemagner traded hands several times, and was expanded and renovated several times before being partially reduced to rubble during a rebellion in the 19th Century. After that, it was generally abandoned, although local Irish rebels hid caches of weapons and ammunition in the castle during the Irish revolution. Today, the ruins of the castle still stand in the town of Castlemagner. Notable people with the surname include:
