They were Irish-American coal miners in eastern Pennsylvania who organized a secret society in 1854. The Molly Maguires aimed to wage a campaign of violence against mine owners and operators. The name of the group came from a society in Ireland that used physical force to fight ruthless landlords. The American miners became determined to defeat their oppressors at all costs. Their numbers grew, and in the decade following the Civil War (1861–65), the Molly Maguires were active both as agitators, and it would later be revealed, as assassins. In 1875 the group incited a coal miners strike, which was broken by the detective work of Irish-American James McParlan (1844–1919), a Pinkerton guard hired by Philadelphia and Reading Coal and Iron Company to infiltrate the Molly Maguires. McParlan revealed the identities of gunmen responsible for the deaths of nine mine company foremen. Several members of the secret society were arrested, tried and convicted (in 1876), and hanged (in 1877) for the crimes. American sympathies for the plight of the miners were diminished by the headlines proclaiming the terrorist activities of the Molly Maguires. The society dissolved by 1877. Their presence, however, was long felt in the anthracite coal fields of Pennsylvania, where company police monitored activities in the mines, and effectively intimidated many miners from organizing.