The Protestant churches of the North in particular preached against slavery, blacks joined these churches and founded associations such as the Colony of Wilberforce within their enclaves. There was the “First Annual Colored People's Convention” in Philadelphia. They became more assertive, courageous and confrontational. Attempts were regularly made to rescue other slaves even when some were with their masters. Around this time, an all-black school opened in New York, and education was no longer a limited commodity. Southern plantation owners were very tough, growing cotton, sugar and tobacco. They were entirely dependent on slave labor and were strongly opposed to the abolition and emancipation of slaves. Their plantations were managed by overseers. Slaves were also classified based on skills, with those with better skills granted more privileges than others. Abolitionists were mostly Northerners who devoted time and effort to abolishing the slave trade and emancipating all slaves. The northern state was against the slave trade and began passing legislation to stop it. A notable abolitionist was William Garrison, who founded the American Anti Slave Society. Some notable blacks