During the era of slavery in the United States, the education of African-Americans, enslaved and free, was often discouraged, except for religious instruction, and eventually made illegal in many of the Southern states. It was believed that literacy was incompatible with the institution of slavery and could ultimately lead to its downfall through rebellion and educated blacks demanding the same rights that whites enjoyed. Nonetheless, both free and enslaved African-Americans continued to learn to read and write as a result of the sometimes clandestine efforts of African Americans themselves, as well as schools and informal education that operated during this period. In addition, slaves used storytelling, music and crafts to pass along cultural traditions and other information.