This book presents rare evidence about the lives of three African women in the sixteenth century--the very period from which we can trace the origins of global empires, slavery, capitalism, modern religious dogma and anti-Black violence. These features of today's world took shape as Portugal built a global empire on African gold and bodies. Forced labour was essential to the world economy of the Atlantic basin, and afflicted many African women and girls who were enslaved and manumitted, baptised and unconvinced. While some women liaised with European and mixed-race men along the West African coast, others, ordinary yet bold, pushed back against new forms of captivity, racial capitalism, religious orthodoxy and sexual violence, as if they were already self-governing. Many Black Women of this Fortress lays bare the insurgent ideas and actions of Graca, Monica and Adwoa, charting how they advocated for themselves and exercised spiritual and female power. Theirs is a collective story, written from obscurity; from the forgotten and overlooked colonial records. By drawing attention to their lives, we dare to grasp the complexities of modernity's gestation.