Coal was a major resource in the county and, as the nation developed industry, the region's coal was exploited in the coal mining industry. Given the harsh conditions of mining, labor attempted to organize to gain better working conditions and pay, beginning in the early 20th century. What was called the Harlan County War in the 1930s consisted of violent confrontations among strikers, strikebreakers, mine company security forces, and law enforcement. These events resulted in the county being called "Bloody Harlan." After the Battle of Evarts, May 5, 1931, Kentucky governor Flem D. Sampson called in the National Guard to restore order.