Wyatt Berry Stapp Earp was born on March 19, 1848, the fourth child of Nicholas Porter Earp and his second wife, Virginia Ann Cooksey. He was named after his father's commanding officer in the Mexican–American War, Captain Wyatt Berry Stapp, of the 2nd Company Illinois Mounted Volunteers. Some evidence supports Wyatt Earp's birthplace as 406 S. 3rd St. in Monmouth, Illinois, though the street address is disputed by Monmouth College professor and historian William Urban. Wyatt had seven full siblings — James, Virgil, Martha, Morgan, Warren, Virginia, and Adelia — as well as an elder half-brother, Newton, from his father's first marriage.