In 1880, San Francisco passed an ordinance that required operators of laundries in buildings not made of brick or stone to apply for a permit to continue operation. At the time, 320 of the laundries in San Francisco were constructed of wood. Yick Wo and Wo Lee (defendants) were laundry operators of Chinese descent. They and over 200 other laundry operators of Chinese descent sought permits to continue their operations. All but one of their requests were denied. However, 80 of 81 similarly situated laundry operators who were not of Chinese descent were granted permits. Yick Wo and Wo Lee were fined and imprisoned after they continued to operate their laundries without permits. Yick Wo appealed to the California Supreme Court, which affirmed his conviction. Wo Lee filed a habeas corpus petition in federal court, but the court denied relief. Yick Wo and Wo Lee appealed to the United States Supreme Court.