on strike. Nearly all the miners joined the UMW (United Mine Workers) on August 18, and within two days almost all the mines in the region had closed due to the spreading strike. Many Slavic miners had not joined the nascent United Mine Workers, both because of ethnic discrimination exhibited by English-speaking and American miners but also because of the poor relationships between unionized miners and the former strikebreakers. But worsening working conditions and a UMW call for a 15 percent wage increase drew many Slavic miners into the union. The first wave of the strike ended on August 23, after the company agreed to pay overtime, bring wages up to the regional average, allow miners to see their own doctors when injured, and no longer force miners to live in company-owned housing. A second strike began on August 25. Teenaged breaker boys at the A.S. Van Wickle coal breaker in the nearby village of Colerain struck for higher wages as well. When Van Wickle attempted to use Slavic workers as strikebreakers, the Slavs joined the strike instead. Although the strike spread to two other nearby coal works, the company quickly agreed to raise wages up to the regional average and the strike ended on or about August 28. But when the new pay rates were announced on September 1, only a limited number of workers received raises. Management did agree to treat Slavic workers more fairly, but the mine owners reneged on their other promises. The strikes resumed. On September 3, 3,000 workers marched on four mines, shutting them down. The mine owners' private armed force, the Coal and Iron Police, proved too few in number to break the strike, so the owners appealed for help from Luzerne County Sheriff James F. Martin. Martin established a posse of about 100 English and Irish citizens to prevent any further marches from occurring. Within five days, 8,000 to 10,000 miners were on strike. On September 8, mine owners demanded that the sheriff of Schuylkill County arrest several thousand miners who had assembled near Pottsville and had forced a mine to shut down, but the sheriff refused. Massacre On Friday, September 10, about 300 to 400 unarmed strikers—nearly all of them Slavs and Germans—marched to a coal mine owned by Calvin Pardee at the town of Lattimer to support a newly formed UMW union. Their goal was to support the newly formed