Please feel free to leave comments quoting your favourite excerpts from these and why they speak to you.
A Vindication of the Rights of Women (1792) by Mary Wollestonecraft
With Strictures on Political and Moral Subjects
It would be an endless task to trace the variety of meannesses, cares, and sorrows, into which women are plunged by the prevailing opinion, that they were created rather to feel than reason, and that all the power they obtain, must be obtained by their charms and weakness.
On the Subjection of Women (1869) by John Stuart Mill (and probably Harriet Taylor Mill)
An essay partnering Mill’s “On Liberty”, an analysis on utilitarian philosophical grounds.
That the principle which regulates the existing social relations between the two sexes–the legal subordination of one sex to the other–is wrong itself, and now one of the chief hindrances to human improvement; and that it ought to be replaced by a principle of perfect equality, admitting no power or privilege on the one side, nor disability on the other.
NB: It’s an interesting example of the US-centricity of the internet that my first searches on “early feminist writing” were all links to writers from the Second Wave of Feminism, the US Women’s Liberation Movement in the 1960s-70s. Great writings, but not that early, to me. These much earlier writings, written in measured, stately language to counter the stereotype of women as overly emotive and unable to reason, are an excellent source for the philosophical fundamentals.