On one side were Wyatt Earp , his brothers Morgan and Virgil Earp, and Doc Holliday. On the other side were brothers Tom and Frank McLaury and Billy Clanton. It is said that the McLaury brothers had repeatedly threatened the Earps because they interfered with their illegal activities but the circumstances surrounding the gunfight and the events of the day have been the subject of extensive discussion.
Tom and Frank McLaury, the main protagonists on one side were certainly Scotch-Irish, and the Earp family, the main protagonists on the other side, were also of Ulster descent.
The first emigrant, Thomas Earp (1631-1720), was born in the Barony of Fews in county Armagh and emigrated from Ulster to America at the end of the 17th century.
Josiah Earp was the first 'Fighting Earp', enlisting in the Colonial Army in Maryland in 1789. Soon after the war Phillip Earp moved to Kentucky, which is where Wyatt's grandfather, Walter Earp, raised most of his children. Walter was a schoolteacher, a JP and a Methodist Episcopal preacher.
Walter married Martha Ann Early (1790-1880) from North Carolina and they were the parents of Nicholas Porter Earp (1813-1907).
In 1840 he married his second wife, Ann Cooksey, and in 1847 the family moved to Monmouth, Illinois. They were the parents of Wyatt Earp, who was born on 19 March 1848.