Although that escape attempt was an early testament to the power of her will, de Cleyre's years in the convent would actually help shape her particularly American brand of Anarchism. She considered herself an "Anarchist without adjectives," meaning that instead of breaking off into a sect and arguing with other Anarchists, she thought it important that everyone who believed in Anarchism support each other in order to further their common goals. From reading and talking to people about de Cleyre and Goldman, I've found that de Cleyre's identification as an Anarchist without adjectives is a significant part of what separated her from Goldman. Another of the biggest differences between the two is that while Goldman and her ideas were originally European, de Cleyre's insistence on freedom was very much shaped by the tradition of American transcendentalism. She read Thoreau and wrote poetry influenced by nature.
De Cleyre was also influenced by Mary Wollstonecraft. She was a feminist because she held the radical belief that every human should be totally free. In her awesome 1890 essay, "Sex Slavery," she declared that conventions of dress, standards of purity, and the institution of marriage were all prisons for women. "The question of souls is old," she wrote. "We demand our bodies, now."
Throughout her short life (she died at 45), de Cleyre suffered from chronic illness and depression. But what amazes me about her is that despite her personal suffering, she was intensely focused and incredibly compassionate. In 1902 a former student of de Cleyre's shot her three times. Predictably, he claimed that he was in love with de Cleyre and that she had broken his heart. Not only did de Cleyre survive, during her recovery she worked to raise money for her shooter's lawyer fees so he could be released from prison. She wrote: "I think this is a case where all Anarchists are concerned that the world may learn our ideas concerning the treatment of so-called 'criminals.'" Even though she had renounced violence, it was against what she believed to allow anyone, even someone who had tried to kill her, to be imprisoned.
If you want to learn more about Voltairine de Cleyre, I suggest Exquisite Rebel: The Essays of Voltairine de Cleyre—Anarchist, Feminist, Genius, edited by Sharon Presley and Crispin Sartwell.