In 1755, Benezet left the Friends' English School to set up his own school, the first public girls' school on the American continent. His students included daughters from prominent families, such as Deborah Norris and Sally Wister. In 1770, he founded the Negro School at Philadelphia for black children. There was a growing free black community in Philadelphia, which increased after the state abolished slavery. Abolitionist sympathizers, such as Abigail Hopper Gibbons, continued to teach at Benezet's Negro School in the years before the American Civil War. In 1775, he helped found the first anti-slavery society, the Society for the Relief of Free Negroes Unlawfully Held in Bondage. Eight years later in 1783, Benezet wrote a letter to Charlotte of Mecklenburg-Strelitz discussing "the cruelty of slavery and his opposition to the slave trade." After Benezet's death, Benjamin Franklin and Dr. Benjamin Rush reconstituted this association as the Pennsylvania Society for Promoting the Abolition of Slavery. Legacy In 1817, the abolitionist Roberts Vaux published a biography about Anthony Benezet. Works Observations on the inslaving [sp], importing and purchasing of Negroes. With some advice thereon, extracted from the Epistle of the yearly-meeting of the people called Quakers held at London in the year 1748., 1760 This brief work, written while Benezet was teaching at the Quaker Girls' School in Philadelphia, was the author's first publication to draw on sources documenting the African trade in slavery. An Epistle of Caution and Advice, Concerning the Buying and Keeping of Slaves, 1754 A short account of that part of Africa inhabited by the negroes, 1762 A Caution and Warning to Great Britain and her Colonies, in a short representation of the calamitous state of the enslaved negroes in the British Dominions. Collected from various authors, etc., 1767 Some Historical Account of Guinea ... With an inquiry into the rise and progress of the slave-trade ... Also a republication of the sentiments of several authors of note on this interesting subject; particularly an extract of a treatise by Granville Sharp, 1771 The potent enemies of America laid open : being some account of the baneful effects attending the use of distilled spirituous liquors, and the slavery of the Negroes : to which is added, The happiness attending life, when dedicated to the honour of God, and good of mankind, in the sentiments of some persons of eminence near the close of their lives, viz. the Earl